1. When will the Nexus be released? What's cheaper?

The Galaxy Nexus is already available in the U.K. and will be available in December in the U.S. (via Verizon Wireless) and Canada. In the UK, the Galaxy Nexus is available contract-free for GBP515 at Clove technology for GBP515, compared to GBP499 for the iPhone 4S. In Australia, a contract-free Nexus is already being sold by online retailers Mobicity and Kogan.

The iPhone 4S is already available in most countries. Phone 4S comes in either black or white and is available for US$199 on two-year contracts with major networks. Apple Stores and other retailers are accepting orders for unlocked versions of the iPhone 4S. The unlocked 16 GB model is priced at $649, the 32 GM is at $749 and the 64 GB is priced at $849.

2. How do the new phones differ from previous and other models?

The Galaxy Nexus could be the finest Android handset to date. Co-developed by Samsung and Google, the Galaxy Nexus is the first device to run Google's just-released Android 4.0, a.k.a. Ice Cream Sandwich and an HD ready display. The latest Android update gives users complete control over the amount of mobile data used and offers state-of-the-art facial recognition technology to unlock the device. Several existing Android devices from HTC and Motorola will receive free software updates so that they, too, can run this OS.

Aside from software, the Galaxy Nexus has a bold new design -- it has no physical buttons on the front, and instead features on-screen soft keys embedded into the system software. The Galaxy Nexus has an LED notification indicator, promptly alerting you of any activity.

The iPhone 4S has the same design and form factor as the 4th generation iPhone. The phone though claims to be "all new inside", now having an A5 dual-core processor, a more advanced camera and a virtual assistant, and "world phone" capability.

iPhone 4S also introduces Siri, an intelligent assistant that helps you get things done just by asking. Siri understands context allowing you to speak naturally when you ask it questions.

3. Does a 4-inch-plus screen make the device bulky?

The Galaxy Nexus measures 2.67 inches (135 mm) x 5.3 inches (135 mm) x 0.35 inches (8.94MM), thanks to its jumbo-sized 4.65-in. display. But despite those figures, the phone is still sleek, thin and light -- weighing in at just 4.8 ounces.

The iPhone 4S just has a 3.5-inch screen, which dwarfed by HTC, Samsung and Motorola phones that have big-but-skinny form factors. The phone measures 2.31 inches (58.6 mm) x 4.5 inches (115.2 mm) x 0.37 inches (9.3 mm) and weights just 4.9 ounces (140 grams).

The Nexus is actually thinner and lighter than the iPhone 4S.

It appears to be better than the iPhone 4s. But will it sell?

4. Which is the prettier phone?

Size aside, the Galaxy Nexus looks similar to the Galaxy S II, although the Nexus has more rounded edges and a contoured display.

The Samsung Galaxy Nexus is stylish, with its 4.65 inch display and svelte profile.

According to Engadget editor Darren Murph, the Galaxy Nexus was "smooth as ever. Without question, this is easily the slickest, most polished version of Android yet.

iPhone 4S has the same thin glass and stainless steel design of the iPhone 4. Noting of the "why fix when it ain't broken" argument, the device designed by Jonathan Ive is still one of the most gorgeous looking phones in the market today. But the iPhone 4S has lost the "thinnest smartphone" claim to the likes of the Motorola DROID RAZR, which is just 7.1 mm thick, although it's 11.1 mm thick on its "bump" on top.

5. Which has a better display?

The screen is a 4.65-inch Super AMOLED one with a 1280 x 720 pixel resolution. The Galaxy Nexus uses a screen based on Samsung's new HD Super AMOLED technology, which offers rich and brilliant colors, crisp and clear text and images. The Nexus has considerably higher screen resolution than the iPhone 4S 3.5-inch screen's 640 x 960 image resolution. The iPhone 4S though offers higher pixel density at 326 ppi, compared to the Nexus' 313 ppi.

6. Is the Nexus more powerful than the iPhone 4S?

The Galaxy Nexus has dual core chipset clocked at 1.2GHz, and 1GB of RAM. Apple has a dual-core A5 chip delivers up to twice the processing power and up to seven times faster graphics than iPhone 4 and 512 MB of RAM.

The Nexus has a faster CPU clock speed at 1.2 GHz, compared to the iPhone 4S's 0.8 GHz. The Nexus also has twice the RAM memory.

7. Which has more battery life?

The Galaxy Nexus has a 1,750 mAh battery, compared to the iPhone 4S's 1,418 mAh battery. While the newest Apple device has been in the headlines for its battery life issues, the Nexus has been praised for its outstanding battery life. The Nexus is estimated to have 24 percent more battery life.

8. What do the benchmarking tests say?

AnanTech's benchmarking found that Samsung Galaxy Nexus came out on top for browsing speed, making it faster than any phone on the market, including the iPhone 4S (which came in second). In a second set of benchmarks, the Galaxy Nexus came out on top, with the iPhone 4S coming in third.

However, the Galaxy Nexus lost out to the iPad 2, the iPhone 4S and the Samsung Glaaxy S 2 when it came to graphics.

9. What are new with Android and iOS?

Ice Cream Sandwich is designed to be a blend of the Android phone and tablet operating systems. ICS reduces reliance of menus to perform tasks, now including more user-friendly icons, and these dynamically change according to whatever program is opened.

New features include facial recognition to unlock the phone.

iPhone 4S comes with iOS 5, which claims to be the world's most advanced mobile operating system. iOS 5 includes over 200 new features including Notification Center, an innovative way to easily view and manage notifications in one place without interruption and iMessage, a new messaging service that lets you easily send text messages, photos and videos between all iOS 5 users. iOS 5 is available as a free software update to old models like the iPhone 4 and iPhone 3GS.

10. Which has a better camera?

The Galaxy Nexus' rear- and front-facing cameras capture 5- and 1.3-megapixel images, respectively, and it records video in full 1080p HD quality.

The iPhone 4S has an 8-megapixel rear facing camera and a VGA front facing camera. The 8 megapixel sensor of the iPhone 4S has 60 percent more pixels than the iPhone 4. The camera has a new custom lens, a larger f/2.4 aperture and an advanced hybrid IR filter that produce sharper, brighter and more accurate images. The iPhone 4S can also now record video in full 1080p HD resolution and has a new video image stabilization feature.

While the iPhone 4S is winning in terms of the size of the megapixel, it's the quality of the optics that matters, says

Geek.com's Russell Holly

Russell points out that the Galaxy Nexus's 1.3 MP front facng camera is the first device to shoot in 720p. The iPhone 4S's FFC camera shoots a 640 x 480 resolution at best. He says that whle both cameras do a great job recording video and video chatting. However, FaceTime or Google Chat on a larger or HD screen, the Nexus has the advantage.

Unlike the Nexus, the iPhone 4S has a dedicated camera button, making it easier to take snapshots using the Apple phone.

11. How effective are their unique features?

The facial-recognition feature, which allows you to unlock the phone, is not very reliable. The facial recognition won't work during low lighting and in other poor conditions. You can actually unlock the phone using the owner's photo.

While the iPhone 4S's Siri is revolutionary, the built-in voice assistant won't do basic tasks like voice-to-text when the network is down. While Siri can get weather reports, set meetings, send text messages, read e-mails aloud and search through your contacts, among other tasks, the assistant can't open apps like Twitter or Facebook, and it can't take pictures. The iPhone 4S is designed to be a world-phone with its GSM/CDMA antenna but Siri only recognizes English, French and German.

The device has sold 4 million in the first three days. But will the device that recycled the design of the 4th generation iPhone have legs?

12. Are the devices bug-free?

Users of the Nexus are complaining that the volume is changing erratically. Videos on YouTube show how interference caused by another handset nearby disrupts the volume of the Nexus.

Google and Samsung has confirmed the issue, saying they already had a fix and the phones would be updated "as soon as possible.

Apple has bragged that the iPhone 4S will have 200 hours standby time (iPhone 4 300 hours), or 8 hours talk time on 3G (iPhone 4-7 hours), or 14 hours talk time on 2G, or 6 hours 3G browsing, or 9 hours Wi-Fi browsing. But iPhone 4 users have been complaining that the iPhone 4S's battery don't last as long as advertised.

Apple has released a software update, the iOS 5.0.1 to fix the battery bug. But somer users are still complaining after downloading the update.

To contact author directly, e-mail c.fernandez@IBTimes.com.au