Today is D-Day for Samsung as the company embarks on what experts perceive as its biggest smartphone launch to date, the Galaxy S4 global debut, likely eclipsing what was seen in 2013 when the million-selling Galaxy S3 was rolled out.

That proved a rousing success as the S3 delivered over 40 million units buys for Samsung and it is inevitable that the new flagship is greeted with higher expectations. According to Jefferies analyst Peter Misek, the South Korean tech is building some 100 million units of the Galaxy S4 and Samsung is upbeat that the stocks will be depleted even before the arrival of the next Galaxy S iteration.

It is not remote, Mr Misek said, that Samsung will achieve such feat and probably in record time. He believes the S4 will fly off the shelves big time, likely clearing the Asian tech giant's self-imposed mark after only three quarters.

And here are the surefire reasons why the Galaxy is an immediate hot-sell.

Cutting-edge hardware prowess

Besides the sex appeal, consumers seek the powers beneath a sleek gadget. They want both sexy and brawn and there's no question that jaw-dropping hardware specs sell and speed up the inventory push out, Business Insider said.

As speculated for the longest time, the S4 is no small phone and will pack a 4.99-inch AMOLED screen that will be fired up by a 1.9GHz quad-core Snapdragon 600. There were indications that in some regions, Samsung's new handset will flex an Exynos muscle, possibly an 8-core CPU.

Classic but sexy look

Departing from its earlier model of housing its smartphone offerings in rainbow-like options, Samsung is keeping its simple for the S4 this year, reports said. No blues, no reds, just the plain but shiny black and white that users would use and flash with pride. Samsung, after all, has achieved a near-Apple status so why not live that reputation to the maximum. It is also believed that the S4 will sell in three configurations - 16GB, 32GB and 64GB with the signature storage expansion capability.

Cool cam features

Device manufacturers are racing to install the best sensor possible to smartphone cameras and Samsung is no exception. Its rivals are using 13MP on the main shooter and there's no reason to believe that the firm is deviating from that template.

Yet more notably is what else can consumers do with the snapper that comes with the S4? Samsung will make use of Android's Photosphere technology and fuse it with Samsung Orb, experts said. The result will enable users to capture images in panorama - in a 360 dimension actually.

Smartphone as virtual cash

Samsung has displayed with the S3 that file-sharing is cool thanks to S-Beam which utilises the near field communication (NFC) technology. For the Galaxy S4, more of that flavour will be seen and this time around users can load up cash values to Samsung Wallet for use on stores with compatible NFC terminals. That would mean shoppers can splurge by simply brandishing their cool Galaxy S4 handsets. Initially, the added premium if for Visa cardholders only but major companies should be jumping on board in no time.

Superfast mobile broadband access

Of course it is a given that Samsung will include LTE on its premier phone but it's comforting to know that network providers are supporting what the company has to offer. In UK, two major carriers have confirmed that indeed the Galaxy S4 is LTE capable and it able to access their infrastructures. UberGizmo identified them as Three and EE. More telcos from around the world should follow suit.

Galaxy S4 wishlist?

It was widely reported that eye-tracking front cam will come with the S4, which would allow users to scroll messages they read through eye movement. Hip as it may be, it is unlikely that the feature will make it to the Galaxy S4, Bloomberg News said. "Eye scrolling won't be in the Galaxy S4, though it may appear in future versions of the phone. There will be more simplified uses of eye-tracking technology, such as the ability to pause videos when the user's eyes move away from the screen," Bloomberg added.

Another awesome addition would be gesture-controlled functions of the new Samsung flagship, in which users can "answer a call by simply lifting the phone to their ear or even to click icons by hovering their finger over the screen," Business Insider said. However, the chance is higher that Samsung fans will have to wait for the next Galaxy S edition to enjoy this feature.