Tablets have become a must-have item, with estimates saying that four out of five persons intend to buy a tablet as a gift this Christmas.

Tablets aiming to challenge Apple Inc.'s iPad, which has 70 percent of the market, are being launched at an unprecedented pace. But what tablet you should write in your Christmas wish-list or buy list actually depends on your preferences.

You don't have to pay $600 for a media tablet if you plan to read an e-book 90% of the time. If you are planning to just surf the Internet rather than downloading an app, pick a tablet with Adobe Flash support. If you're worried over malware, an iPad has access to safe and secure apps. For serious blogging or for picture taking, an Amazon tablet won't be a good bargain.

Here's feature-on-feature guide to help you decide on what tablet to buy for you or for the people on your holiday shopping list:

* Screen

Samsung Galaxy Tab 10.1: 10.1-inch Super PLS display

Motorola XOOM 2: 10.1-inch HD display with Corning Gorilla Glass

ASUS Eee Pad Transformer Prime: 10.1-inch Corning Gorilla Glass

Apple iPad 2: 9.7-inch LED-backlit glossy widescreen

Sony Tablet S: 9.4-inch screen with Sony's TruBlack display

Amazon Kindle Fire: 7-inch Gorilla Glass display

Barnes & Noble Nook Tablet: 7-Inch VividView Color Touchscreen

A bigger screen means there'd be a bigger screen for movies and games, and typing, and, thus, requiring less zooming and scrolling. Although a small screen real estate limits functionality, it makes the device more portable.

* Resolution

Nook Tablet: 1024 x 600 at 169 ppi

Kindle Fire: 1024 × 600 at 169 ppi

Sony Tablet S: 1280 x 800 at 161 ppi

Motorola XOOM 2: 1280 × 720 at 160 ppi

Samsung Galaxy Tab 10.1: 1280 × 800 at 149 ppi

Apple iPad 2: 1024 × 768 at 132 ppi

ASUS Transformer Prime: 1,280 x 800

Higher pixel density (ppi) provides better picture quality and clarity. While the Nook and Fire offer small screen real-estate, their screens offer remarkable clarity with their high resolution display of 169 pixels per inch.

Barnes & Noble's new tablet

* Processor and RAM

ASUS Transformer Prime: 1.3 GHz NVIDIA Tegra 3 quad-core processor with 1 GB RAM.

Kindle Fire: 1 GHz TI OMAP 4 4430 (dual core) with 512 MB RAM

iPad 2: 1 GHz dual-core Apple A5 with 512 MB RAM

Galaxy Tab 10.1: 1 GHz dual-core Nvidia Tegra 2 with 1 GB RAM

Motorola XOOM 2: Dual core, 1.2 GHz with 1 GB DDR2 SDRAM

Nook Tablet: 1GHz TI OMAP4 (dual-core) processor with 1GB RAM

Sony Tablet S: 1 GHZ dual-core NVIDIA Tegra 2 mobile processor with 1 GB RAM

Quad-core processors are designed to be twice-faster than dual-core chips and would make tablets as powerful as laptops. With its NVIDIA Tegra 3 quad-core processor, the Transformer Prime promises extreme multitasking capabilities, lightning fast app loading, a rich and fluid web experience, full 1080P HD video playback or recording without compromising battery life, and console-quality gaming.

While the Asus Eee Pad Transformer is the first tablet to go quad-core, such processors will likely be the standard for high-end tablets next year. HTC, Lenovo and other device-makers are said to be prepping their own quad-core tablets for release next year.

Qualcomm has already announced that its quad-core Snapdragon chips, designed to run Microsoft's upcoming Windows 8 OS, will appear in tablets in the second half of next year.

Not yet available in the U.S.

* Camera

ASUS Eee Pad Transformer Prime: 1.2MP front camera plus 8MP rear camera with continuous LED flash, full 1080 video recording,

iPad 2: VGA front camera plus 0.7 MP rear camera for 720p HD video recording, still camera with 5x digital zoom.

Galaxy Tab 10.1: 2 MP front camera plus 3 MP rear camera for 1080p HD video recording, with LED flash and autofocus.

Motorola XOOM 2: 1.3 MP front camera + 5 MP 720p rear camera

Sony Tablet S: 3 MP front-facing camera plus 5 MP rear-facing camera with 720p HD capability for video capture, autofocus, image stabilization but has no LED flash.

Kindle Fire, Nook Tablet: No front or rear camera

The front-facing camera allows you to have video calls. The Eee Pad Transformers' continuous LED flash allows you to record videos at night. The Tablet S's cameras have exciting features but interestingly have no LED flash. The Kindle Fire doesn't have a camera, but would you really carry your tablet up in the air to take pictures?

* Storage

ASUS Eee Pad Transformer Prime: 32 GB / 64 GB internal storage plus ASUS cloud storage

iPad 2: Starts at 16 GB of internal storage plus free 5 GB of storage at iCloud

Galaxy Tab 10.1: Starts at 15 GB of flash memory

Motorola XOOM 2: 16 GB internal flash memory

Nook Tablet: 16 GB internal plus plus free Nook Cloud storage

Kindle Fire: 8 GB of internal storage plus free Amazon Cloud storage for all Amazon content

Sony Tablet S: 15 GB / 32 GB storage plus up to 32 GB via SD card

Cloud services offer incremental memory and flexibility when accessing thru other devices. Although Amazon offers unlimited storage at Amazon Cloud, you can't do much on an 8-gig Kindle Fire when offline.

* Networking and connectivity

iPad 2: Wi-Fi + GSM/CDMA plus Bluetooth 2.1+EDR

Galaxy Tab 10.1: 3G/4G connectivity, Wi-Fi, Bluetooth plus HDMI

Motorola XOOM 2: Wi-Fi, micro-HDMI 720 p, micro-USB 2.0 plus Bluetooth 2.1

ASUS Eee Pad Transformer Prime: Wi-Fi, Bluetooth 2.1+EDR but no 3G or 4G.

Sony Tablet S: Wi-Fi but no 3G/4G compatibility for now

Kindle Fire: Wi-Fi plus USB 2.0

Nook Tablet: Wi-Fi

The Kindle and Nook won't give you the ability to connect to the Internet via the cellular networks. This means that when you are in a bus or in an exciting crocodile adventure in Outback Australia, you won't be able to access your movies that you have stored in the cloud. The old Kindle, the e-book reader, surprisingly had 3G access.

* Battery

ASUS Eee Pad Transformer Prime: 25 Wh Li-polymer battery offers up to 12 hours, but when combined with the mobile dock, it lasts up to 18 hours.

iPad 2: 25 Wh lithium-ion for up to 10 hours surfing the Web on Wi-Fi, watching videos or listening to music.

Galaxy Tab 10.1: 6000 mAh for up to 9 hours on normal usage

Motorola XOOM 2: 10+ hours Web usage or over 1 month stand-by

Nook Tablet: 9 hours of video watching

Sony Tablet S: 5000 mAh Li-Ion for up to 8 hours of video playback and web browsing using WI-Fi.

Kindle Fire: 4400 mAh for up to 7.5 hours of video playback wireless off)

* Weight, dimensions

Nook Tablet: 400 grams, 206 mm x 127 mm x 12 mm

Kindle Fire: 413 g, 190 mm x 120 mm x 11.4 mm

iPad 2: 600 g, 241 mm x 186 mm x 8.8 mm

Galaxy Tab 10.1: 565 g, 256.7 x 175.3 mm x 8.6 mm

Motorola XOOM 2: 599 g, 253.9 mm x 173.6 mm x 8.8 mm

ASUS Eee Pad Transformer Prime: 586 g, 263 mm x 180.8 mm x 8.3 mm

The Galaxy Tab 10.1 is one of the lightest and thinnest 10-inch tablets.

* Platform

Kindle Fire: Customized Android 2.3 Gingerbread OS plus split browser called Amazon Silk, support for Adobe Flash

iPad: iOS 5, which Apple says boasts of 200 new features, which Apple says takes "a mobile operating system that was already years ahead of anything else and moving it even further ahead.

Sony Tablet S, ASUS Eee Pad Transformer Prime, Galaxy Tab and Motorola XOOM 2: Android Honeycomb. Unlike iOS, Android has Adobe Flash support. Honeycomb improves the touch keyboard; adds OpenGL acceleration, Renderscript 3D graphics and multi-core processor support; and offers full tabbed browsing and double tap zoom. ASUS says the Transformer Prime can be upgraded to Android 4.0 Ice Cream Sandwich in December.

Nook Tablet: Customized Android 2.3 Gingerbread. Home screen displays shelf of recently opened apps, books or magazines, plus thumbnails of recently accessed books and recommendations for similar content that you may want to purchase.

* Multimedia services

Samsung Galaxy Tab 10.1: TouchWiz US interface, which includes social hub for unifying messaging from Facebook and other services and a reader's hub for up to 2 million e-books. Samsung doesn't sell apps, movies or music like Apple or Amazon. Users of the device can buy or download thousands of apps and games are available in the Android Market.

iPad 2: iCloud, iTunes, Apple App Store, access and music library from iTunes Match.

Nook Tablet: 2.5 million books, magazines, and comics plus few thousand apps available at Barnes & Noble. But Barnes & Noble doesn't sell digital music and movies. For music, you need to have subscription to third party vendors like Rhapsody or Pandora, and for videos, you can subscribe to Netflix or Hulu Plus.

Kindle Fire: Like the Nook Tablet, you can subscribe to music and streaming services provided by third party vendors. An exclusive for the Fire is that you can have $79 per year membership at Amazon Prime for unlimited streaming of 10,000 movies and TV shows plus 20,000 apps at Amazon App Store, access to music via Amazon's Cloud Player.

ASUS Eee Pad Transformer Prime: ASUS doesn't sell apps, movies or music like Apple or Amazon. Users of the device can buy or download thousands of apps and games are available in the Android Market.

Sony Tablet S: This Sony Tablet device is the first PlayStation Certified tablet, offering out-of-the-box gaming with 'Crash Bandicoot' and 'Pinball Heroes' built-in. In addition, the Tablet S has, among others, Video Unlimited, which provides latest releases from every major movie studio to rent or own (offered at device launch with limited content and more content will continue to be released over time) and Music Unlimited, which offers instant access to a global catalog of over 10 million songs from every major record label.

Although it is at the end of the line in terms of specs, the Amazon tablet is still the ideal gadget for eReading, watching videos or listening to music given that it has access to Amazon's content ecosystem. For serious gamers, Sony Tablet S would be most attractive, given the device's integration to the PlayStation Network.

Apple's iPad 2 had sales of 11 million units in the most recent quarter

* Enterprise features

Motorola XOOM 2: Active Sync for work email, contacts and calendar plus pre-loaded Citrix Receiver and Citrix GoToMeetin

Galaxy Tab 10.1: Support for communication systems such as Microsoft Exchange ActiveSync,Virtual Private Network solutions. See http://www.samsung.com/us/article/samsung-approved-for-enterprise

ASUS Eee Pad Transformer Prime: Built-in apps include note-taking app SuperNote and Polaris Office, for reading, editing or creating Word, Excel and PowerPoint (MS Office 97-2007) compatible files. Apps like Asus WebStorage, MyNet, MyCloud, File Manager, and Asus sync are also built-in.

iPad 2. iWorke suite, Office 2 HD, and Pages allow you to edit Microsoft Office documents and Excel spreadsheets. Business related apps like Citrix's GoToManage are available at the Apple App Store.

Nook, Amazon Fire: Limited or no enterprise features.

* Unique features

NOOK Tablet: Free NOOK support and Wi-Fi in all Barnes & Noble stores. Has Microphone to record narration for kids' Read and record books.

ASUS Eee Pad Transformer Prime: Boasts a wide 178° viewing angle IPS display, features a "Super IPS" mode, which turns up the brightness to 600 candelas per square meter, for better outdoor reading, plus has a $149 mobile dock that turns the device into a laptop and gives dditional 6 hours from 24Wh battery in the dock, and a USB port and SD card slot.

Sony Tablet S: With a unique wrap design, The Tablet S doesn't look like your usual slate. The 9.4-inch Tablet S has an ergonomic, asymmetric design -- rounded and thick on the upper side and significantly slimmer towards the lower side.

iPad 2: Over 140,000 apps, virtually in all category, for work, "play and everything in between" and optimized for the iPad are available in the App Store.

* Pricing

Kindle Fire: US$199

iPad 2: Starts at US$499

Galaxy Tab 10.1: US$499 for Wi-Fi only, 16 GB model

Motorola XOOM 2: GBP379.99 (US$608)

Nook Tablet: US$249

Tablet S: US$499

ASUS Eee Pad Transformer Prime: Starts at US$499 plus $149 for mobile dock.

Amazon's $199 price tag, plus the site's deep portfolio of digital content make the device a must-buy. Apple, which takes margins of 40 percent from the sale of the iPod, iPad and iMac, won't likely lower prices of the market leading iPad. After Amazon set a price threshold for a tablet, device-makers hoping to challenge the iPad would have trouble introducing new tablets that are as expensive as the iPad.

* Release Date and availability

iPad 2: Apple unveiled the iPad 2 in March 2011 and already available worldwide. The iPad 3 will likely be released in spring or summer of 2012. There are also reports about a 7-inch iPad Mini that Apple would release to fend off the Kindle Fire.

Motorola XOOM 2: Motorola Mobility has unveiled the XOOM 2 in the U.K. and Ireland and is set to release the device later this month. The Motorola XOOM 2 has not yet been released or launched in the U.S. The first edition XOOM, although well received by critics, failed to sell.

Nook Tablet: Barnes & Noble released the Nook Tablet in the U.S. in November.

Kindle Fire: Amazon released the Fire in U.S. in November.

Galaxy Tab 10.1: Samsung released the device in June 2011. The device is already available worldwide except Netherlands and Australia due to injunctions obtained by Apple in patent suits between the two companies. Seven inch and 8-inch variations, as well as a five-inch (the Galaxy Note) are also available.

Tablet S: The device, along with the Tablet P, was made available September.

ASUS Eee Pad Transformer Prime: The first quad-core tablet on the market is set to be available in shelves this month..