We've also got a full Hands on: Samsung Galaxy S3 review too.
What's the point of this you may well ask? Well remember you'll probably be able to get the S2 on some mega cheap deals now the new handset has been announced - and, what's more, we know the Galaxy S3 release date is the end of May.
And, if you don't need to be quite on the bleeding edge of smartphones (and paying through the nose for it) then then Galaxy S2 may well be enough for you.
Samsung Galaxy S3 vs Galaxy S2: Software
Both the Galaxy S2 and the S3 run Android, albeit different versions. Samsung's phone uses Android 2.3.4 (Gingerbread), customised with the TouchWiz 4.0 UI overlay and Swype text input. It's upgradeable to Android 4.x -which the Galaxy S3 comes with by default - Android 4.0.4 to be precise.
Both handsets have Samsung's 'hub' apps in common including the Social Hub, the Games Hub and the Music Hub.
Samsung Galaxy S3 vs Galaxy S2: Processor
The Galaxy S2 was one of the first handsets to featurea dual-core processor when it emerged at Mobile World Congress 2011. Inside the S2, you'll find an Exynos processor (formerly 'Orion'), rated at 1GHz. This was the dual-core follow-up to the successful single-core Hummingbird chip that appeared in the original Galaxy. The S3 by contrast ups the ante to quad-core with a new chip called the Exynos 4 Quad - it runs at 1.4GHz.
According to Samsung, there are performance improvements over the earlier Exynos processor - but that it consumes 20 per cent less power.
Samsung Galaxy S3 vs Galaxy S2: Screen
The Galaxy S3 takes Super AMOLED to a new level with an HD, 1,280 x 720 screen. While it's half an inch bigger than the S2's 4.3-inch, 800 x 480 display, there's no Super AMOLED Plus tech used unlike the S2. But the S3's display has to be seen to be believed and, while the S3 seems to dial down Super AMOLED's massive colour saturation, it's a terrific screen.
Samsung Galaxy S3 vs Galaxy S2: Storage and memory
The Galaxy S2 comes in either 16GB or 32GB models, while the S3 also adds a 64GB model to the list. Both feature 1GB of RAM. There's also a microSD slot in the side of both.
Samsung Galaxy S3 vs Galaxy S2: Cameras
Headlining the Samsung Galaxy S3 is an 8 Megapixel camera with extras that include: autofocus, LED flash, geo-tagging, touch focus functionality, face/smile detection, image stabilisation and 1080p video capture (the S2 also had a 8MP unit). The front camera actually takes a step down - you'll find a 1.2MP 720p camera in the front of the S3 for video calls or self-portraits while the S2 had a 2MP unit. The S3 is also capable of full 1080p HD playback.
Samsung Galaxy S3 vs Galaxy S2: Connectivity
In terms of connectivity, both phones are well-specced. The Galaxy S2 and S3 incorporate 3G/HSDPA and HSPA+ at speeds up to 21Mbps where supported. It's got every band of Wi-Fi covered too and can handle 802.11a/b/g/n with DLNA content sharing and Wi-Fi Direct.
Bluetooth 3.0+HS finishes off the wireless options in the S2, while you get the new and more power efficient Bluetooth 4.0 inside the S3. The S3 can also use MHL to output to a monitor via its micro USB port.
Samsung Galaxy S3 vs Galaxy S2: Location and sensors
At this level, you'd expect most smartphones to feature GPS/A-GPS, a built-in gyroscope, digital compass, plus screen-flipping accelerometer, proximity and light sensors. You won't be disappointed with either phone - though the S3 adds a barometer.
Samsung Galaxy S3 vs Galaxy S2: Dimensions
Like the Galaxy S2, the new S3 is a neatly designed, beautiful-looking handset that measures 136.6 x 70.6 x 8.6mm compared to the S2's 125.3 x 66.1 x 8.49mm. Yes, note the size has gone up across all the dimensions, but the plastic remains which means the weight doesn't reflect the bulk. The S3 weighs in at a respectable 133g compared to the S2's 116g which, if you've held one, you'll have thought was very light indeed.
Samsung Galaxy S3 vs Galaxy S2: Battery life
That bigger screen and quad-core processor need a lot more juice, so the bigger bulk is no doubt down to the bigger battery inside the S3. The Samsung Galaxy S2 boasts a 1650 mAh battery, while the S3 has a 2100mAh battery.
Samsung Galaxy S3 vs Galaxy S2: Verdict
There's no doubting that the S3 is a terrific new handset and it seriously ups the ante on the ageing S2. However, it depends whether you're prepared to pay for the privilege of owing a new model handset - the S3 will come in around the £36+ price bracket per month, while we're seeing some monthly prices for the S2 as low as £21-23.
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Dan (Twitter, Google+) is TechRadar's Former Deputy Editor and is now in charge at our sister site T3.com. Covering all things computing, internet and mobile he's a seasoned regular at major tech shows such as CES, IFA and Mobile World Congress. Dan has also been a tech expert for many outlets including BBC Radio 4, 5Live and the World Service, The Sun and ITV News.