We've all been speculating about it for months and at last the Samsung Galaxy S3 is a reality, announced at the Brand's huge Mobile Unboxed event at Earl's Court in London.

The successor to the Samsung Galaxy S2, the new handset sports a massive 4.8-inch screen, a quad-core processor and a wide range of other interesting features on board.

As the new top-tier Android phone on the block, the S3 is set to go head to head with the likes of the HTC One X, the Sony Xperia S but has it got what it takes to grab the Android crown, and can it turn iPhone 4S fans over to Google's OS?

We went hands-on with the new phone for a closer look...

Samsung Galaxy S3: Build

With a 4.8-inch screen on board, the S3 isn't exactly small. Measuring 136.6 x 70.6 x 8.6mm, the S3 is slightly longer, wider and fatter than the S2 (125.3 x 66.1 x 8.49mm), which may prove to bit a little on the large side for some although the extra thickness may actually make the S3 slightly easier to hold and less likely to slip from your hand, particuarly when taking a photo.

At 133g, the S3 is very slightly heavier than the S2, although only be 3g so if we hadn't have told you, you probably wouldn't have even noticed.

The slightly rounded design means that the new phone has more in common with the looks of the Samsung Galaxy Nexus than with the S2, although the plastic finish on the back feels more premium than its predecessor.

The S3 has the usual Home button along with Settings and Back touch controls on either side, while the front-facing camera has inexplicably moved from the left to the right of the screen.

The brand takes it's 'Inspired by Nature' theme through to the finishes - you can choose from Marble White and Pebble Blue.

Samsung Galaxy S3: Features

There are plenty of new features on board, not least the Smart Stay function which uses eye detection to ensure that the screen

doesn't dim as long as you're looking at it, which could well be useful, albeit a potential drain on on your precious battery life.

Smart Alert means that the phone will vibrate as soon as you pick it up to let you know that you have a notification, presumably if looking at the notification light is slightly too taxing for you. Not exactly a game-changing feature, but something new, nonetheless.

Another new feature is Smart Call which automatically dials the number you're looking at as soon as you lift the phone to your ear when you're in contacts, messages or call log. This sounds like a clever piece of technical wizardy (which is based on proximity sensors and motion detection), but whether it's useful or not will be down to personal preference.

S Voice is essentially voice-activated control that will give you direct access to functions such as the camera, calls, text, the alarms, weather, calendar and music and it'll even work when music is playing. What it won't do is answer you back with pithy retorts, like Apple's Siri.

You'll also be able to watch videos in a (very tiny) pop-up screen whlie multitasking in other apps. We're not entirely sure what this would be useful for, but video conferencing could be the key here.

Social Tag will instantly recognise faces from pics and automatically offer to text the image to the people featured in the image.

All Share PLay enables wireless transfer to all other connected devices while SBEAM will transfer files using an NFC connection, although for bigger files you'll need to go back to Wi-Fi. And it'll only work with other Galaxy S3s.

Samsung Galaxy S3: Screen

The gigantic 4.8-inch screen is probably the phone's most striking feature, and while it's an inch bigger than that of the HTC One X, it's not as square so it doesn't look quite as massive. It's still quite a leap from the S2's 4.3-inch screen, while the pixel density has been upped from 218ppi to 306ppi, with a resolution of 720x1280 pixels. Once again the screen uses Super AMOLED technology, to keep the viewing angle as wide as possible.

Even under the artificial lights of the demo room, we could see that the screen was of excellent quality, but we've to try out in bright sunshine.

Samsung Galaxy S3: Camera

While many were expecting a 12MP camera to land with the new S3, Samsung has stuck a relatively average, but thoroughly decent, 8MP snapper and it will also shoot and play 1080p. Not much has changed since the previous model in terms of specs, but there are a couple of new features.

The burst mode takes contiunous shots at a rate of 6fps, and from that the camea will pick the best shot based on smile detection, blink detection, contrast and blurring. According to Samsung, the camera has zero shutter lag along with an improved shot-to-shot time.

Face Slideshow will zoom in all the faces within a picture if you're viewing your pictures in a slideshow. Does anyone view their phone-based photos in a slideshow? We're not so sure.

You'll also be able to set up rules for photos to be automatically placed in groups based on faces, contacts or location. There's also Face Zoom which means that you can tap on a face when lining up a crowd shot and the camera will zoom in automaticlly. The lack of optical zoom means that this is going to be fairly limited, but we look forward to trying it out in the wild.

We can't help but think that some or these features may be overthinking the problem somewhat. We just want a camera that offers the best quality snaps possible...

Somewhat curiously, the front-facing cam is 1.9MP compared to the S2's 2MP. While this kind of difference will make absolutely no difference at all in practice, it seems a little strange for the specs to be going down rather than up. However, the good news is that you can shoot video in 720p and also capture stills and the same time that you're shooting video.

Samsung Galaxy S3: Performance

The quad-core processor certainly seemed to do the trick in the limited time that we had with the phone. There was barely any lag when switching between home screens and firing up apps.

The S3 sports 1GB of RAM (the same as the S2), while the Flash memory is available in 16, 32 and 64 GB versions, improving on the S2's 16GB offering, while there's also a micro SD card slot should you wish to expand the memory. There's also 50GB of free storage for your content on Dropbox for the next years, which is double what HTC is offering on its HTC One X.

Samsung Galaxy S3: Battery

The S3 packs a 2100mah battery, compared to the S2's 1650mah cell. Obviously we haven't had our hands on the phone long enough determine exactly how much difference this will actually make, the presence of a more powerful processor (not to mention all the extra features) will certainly require more juice.

Samsung Galaxy S3: Verdict

The Samsung Galaxy S3 certainly looks impressive, especially thanks to the zippy operation that results from that quad-core chip.

Some will see the new social, voice and notification features as being compelling reasons to buy the phone. Some will see them as an unnecessary drain on the battery and will spend their first few hours with the phone deciding which of the features to deactivate first.

Either way, there's no denying that the S3 is a powerful phone that could well be a contender for the Best Android Phone crown. We'll just have to see how it performs when we get one in for testing at T3 Towers...

Samsung Galaxy S3 availability: 30 May

Samsung Galaxy S3 price: TBC

Hands-on review by Libby Plummer

Check out our Samsung Galaxy S3 hands-on review video: