Nokia's highly anticipated Lumia 900 is all set to hit the shelves in next few days. And this phone has to do well since besides to Nokia, Microsoft too is depending a lot on the success of this phone.

Through this flagship Nokia phone, Microsoft certainly pins its hope to silence the critics and to make a solid impression in the world of smartphone OS that is until now dominated by Google's Android and Apple's iOS.

According to a very recent CNN report, Apple and Google control a combined 80 percent share of the smartphone market in the US while Microsoft holds a meager 4 percent. But this long-awaited and long-lusted-over Nokia phone will be a game-changer, believe Microsoft.

This year's most-awaited Windows Phone, ensconced in a polycarbonate body, is quite an impressive one. With its striking blue color, 4G LTE compatibility, and top-notch specs, the phone is aptly called iconic, beautiful and fast by Chris Weber, Nokia's president in North America.

Nokia's flagship Lumia handset, Lumia 900, was unveiled at the CES earlier this year and also took home the Best of Show award.

AT&T, the official carrier of the phone in the US, has also announced that Nokia's first 4G Long Term Evolution (LTE) phone will receive a special launch program April 8.

At all levels, this is a notch above anything we've ever done, AT&T device head Jeff Bradley said in an interview with CNET and that includes the launch of the iPhone, he further added.

While the dazzling design, electric blue color (other colors are also being launched soon) and impressive features of the Nokia phone are grabbing eyeballs of the smartphone lovers, we are more excited to see whether the most talked-about Windows Phone is compelling enough to beat our all-time favorite AT&T phones like Samsung Galaxy S II Skyrocket.

Now dive right into the comprehensive spec comparison of two AT&T phones and pick up your best choice.

Size:  Lumia 900 comes with dimensions of 127.8 (height) x 68.5 (width) x 11.5 (depth) mm and weighs 160 grams. On the other hand, Skyrocket will come in dimension of 129.8 (h) x 68.8 (w) x 9.5 (d) mm and weighs 130.5 grams. Though the Nokia handset is heavy, yet you won't feel comfortable when you hold it in the hand while the Samsung phone, which is equally heavy, will make you feel comfy.

Display:  Nokia Lumia 900 sports a 4.3-inch 800 x 480 pixels Super AMOLED Plus capacitive ClearBlack touch-screen with 217 ppi density while Skyrocket touts a 4.5-inch Super AMOLED Plus display that gives a resolution of 800 x 480 pixels with 207 ppi pixel density.

While the Samsung phone's WVGA Super AMOLED Plus display showcases deep hues and amazing clarity, Nokia's ClearBlack Display technology delivers very bright, sharp and saturated colors.

Operating System:  Lumia 900 will run on the latest Microsoft Windows Phone 7.5 Mango and will offer one-touch access to social networking sites along with features like easy grouping of contacts, communication threads and Internet Explorer 9.

According to a PCMag report, the Windows 7 Mango is [F]ull of people-centric features that make it easier to stay in touch with friends and family, to communicate, and to share ideas. It's easier to use than Android, and in many ways slicker than Apple's iOS.

Galaxy S2 Skyrocket, however, runs on Android 2.3 Gingerbread operating system with a promise of upgrading to Google's latest smartphone OS, Android 4.0 Ice Cream Sandwich. While the Korean electronics giant has already launched ICS upgrade for Galaxy S2, no report for OS upgrade for this phone has reached us yet.

Processor:  Lumia 900 comes with a 1.4 GHz Scorpion single-core processor, Qualcomm APQ8055 Snapdragon, Adreno 205 GPU with 16GB internal storage and 512MB RAM. The RAM is undoubtedly on a lower side when compared to Skyrocket's 1 GB RAM. The Skyrocket features a dual-core 1.5 GHz Qualcomm APQ8060 (Snapdragon S3) CPU and accompanying Adreno 220 GPU.

Nokia's single core processor is quite surprising to us as now all the smartphones are come with dual-core and even with quad-core processor. But, hands-on review of the phone has changed our opinion about the single-core phone, which is as fast as any other Android phone available in the market.

Camera: Both the Samsung and Nokia smartphones feature 8 megapixel cameras, but only the Skyrocket can capture full 1080p HD video, while Lumia 900 tops out at 720p. Skyrocket also has an additional 2 megapixel front-facing camera for video calling while the Nokia phone has a 1 MP front camera. Nokia phone, however, sports a Carl Zeiss optics, which, along with its dual-LED flash and autofocus, boost image clarity. Skyrocket also boasts of a plethora of settings to let you tweak the white balance, ISO, metering, focus mode, exposure and contrast of the photos.

3G/4G: Skyrocket comes with HSDPA 21 Mbps, HSUPA 5.76 Mbps and supports 4G LTE whereas according to AT&T, the Lumia phone will provide a blazing fast 4G LTE that speeds 10x faster than 3G.

WLAN/Bluetooth/USB: Skyrocket has Bluetooth 3.0 version, Wi-Fi Direct, DLNA, and Wi-Fi hotspot, Bluetooth EDR stereo, mini USB 2.0 version, and Wi-Fi 802.11 a/b/g/n. On the other hand, Lumia 900 has Wi-Fi 802.11 b/g/n, NFC, Bluetooth 2.1 version with A2DP and EDR, and microUSB 2.0 versions.

Storage:  Skyrocket has a fixed 16 GB internal storage that can be expanded up to 32 GB via microSD card. Lumia 900 comes with 16 GB fixed storage and no microSD card slot.

Battery: Skyrocket comes with a standard Li-ion 1850 mAh battery that gives up to seven hours of talk time and up to 256 hours of standby. Lumia 900 has a standard Li-Ion 1830 mAh (BP-6EW) battery that gives up to 8 hours of talk time, up to 60 hours of music play and up to 300 hours of standby time and up to 7 hours of talk time.

Apps: The Windows platform now offer 65,000 apps, which may not include all the Zynga With Friends games, as well as Draw Something, Pandora, Angry Birds Rio and Temple Run, but you can play Doodle Jump, Super Monkey Ball, Sonic the Hedgehog 4 and others. Some basic apps like clock, calendar, calculator, Internet Explorer 9 (with HTML5 support but no Flash), and Music + Video hub are also there. Microsoft offers Xbox Live integration through the Games hub, an FM radio with Lumia 900 and AT&T preloads a bar code and QR code scanner; AT&T Navigator with turn-by-turn directions; AT&T Radio; and AT&T U-verse Mobile.

But then also the Windows phone lags far behind the Android phone in terms of numbers of apps. The Android marketplace offers as many as 450,000 apps. So with your Galaxy S2 Skyrocket apart from all the Samsung preloaded basic apps and the apps offered by the carrier, you have a world full of apps to explore.

Additional Features:  Lumia 900 has features like HTML5, Adobe Flash, an Accelerometer, gyro, proximity and compass, active noise cancellation with dedicated mic, MP3/WAV/eAAC /WMA player, MP4/H.264/H.263/WMV player, Video/photo editor, Voice memo/command/dial, predictive text input and a document viewer/editor.

Samsung Galaxy S2 Skyrocket packs features like Active noise cancelation with dedicated mic, SNS integration, MP4/DivX/XviD/WMV/H.264/H.263 player, MP3/WAV/eAAC /AC3/FLAC player, Organizer, Image/video editor, Document editor (Word, Excel, PowerPoint, PDF), Google Search, Maps, Gmail, YouTube, Calendar, Google Talk, Picasa integration, Voice memo/dial/commands and Predictive text input (Swype).

Pricing: Nokia's mandate was to supply a quality phone at a lower price and to abide by that, the company has planned to launch the phone at a very affordable price of $99.99 on AT&T. The phone is available on Amazon at a much lower price. Skyrocket is priced at $149.99 with a two-year AT&T contract.