Firstly, it's slightly ahead when it comes to codec support, with the S2 also deciding that it's cool with showing DivX files as well as the normal Xvid/MP4/WMV offerings that the Sensation can manage.
Plus there's the difference in media players too - the S2 has a great video player that lets you manipulate the aspect ratio, where the Sensation only uses the Gallery to jump into videos - with no labels to let you know which is which, something that really irks when you've got loads from a certain series in there.
When it comes to music, things are a little closer, with the Samsung S2 just edging the contest sonically. Bass levels are deeper on the Samsung offering, and the level of crosstalk from the device is minimal, just a shade better than the Sensation.
We're also big fans of the easier music manipulation from the notification bar - the S2 has full track skipping control, where HTC has gone with a single pause and play button. However, we do want to give the Sensation props for having a really cool lock screen widget, with a little piece of spinnable album art to play with.
Winner: Hands down, no contest, the Samsung Galaxy S2. There's a reason Samsung is happy to turn the Galaxy phones into PMPs, and that's the sheer range of functionality and hardware built around media.
A hugely important category for any possible phone buyer, and one we've spent a long time testing and making sure we've come to the right conclusion (even sending back our first Sensation review unit after some decidedly odd results from our initial tests).
The good news is both of the phones will manage to last over a day on a single charge, even with the likes of Push Email and Wi-Fi buzzing away in the background. However, be careful when downloading applications that might not have been fully tested, as we found a few that decided to suck the life unfairly out of our devices.
In terms of the victor here, it really depends what you use the phone for. Under 'normal' usage, by which we mean around an hour of music use, perhaps half an hour of video and push email and social networking applications running in the background, perhaps with a spot of mapping to go with it, the Samsung Galaxy S2 is ahead for battery longevity.
This is mainly down to the decision to put a 1650mAh battery inside the super-slim phone, where HTC has gone with a 1540mAh offering for the Sensation. Why HTC never likes to have a market-leading battery under the hood, we'll never know - this problem could be sorted in a single upgrade.
The only issue when it comes to battery life we can see is the Samsung Galaxy S2's superb screen: you'll find yourself using it a lot more for video and internet browsing, so be ready for the necessary hit in battery life.
Winner: Samsung Galaxy S2 - mostly for daring to pack a bigger battery pack under the hood
Connectivity and storage
We felt this category should be added in as both of the brands have put a lot of effort into getting as much technology under the hood as possible, helping future proof the devices for the future.
Aside from the spectacularly odd decision from Samsung over NFC (announcing it at Mobile World Congress, then mysteriously releasing phones without it, before announcing future models will have it) the Galaxy S2 definitely has the greater amount of functionality built in.
Both phones have HDMI-output through the microUSB slot (although neither have a cable in the box) and both have Bluetooth 3.0 on board, DLNA streaming software and Wi-Fi 802.11b/g/n connectivity. While the Samsung is certainly less powerful when it comes to connecting to Wi-Fi networks (we found up to two bars difference in identical conditions between the Samsung Galaxy S2 and the Sensation) it slightly leads in mobile signal according to our tests.
Where the Samsung Galaxy S2 comes into its own is for things like USB On The Go, where users can plug a USB stick into the phone using the (non-supplied) adaptor, plus an improved DLNA All Share server making it easier to port content to a big screen - although the Sensation is more than half decent at this too.
Faster HSDPA downloads speeds for the Samsung Galaxy S2 - 20.1Mbps compared to only 14.4Mbps for the Sensation - mean it's slightly more future proof when the mobile networks start offering more speed too.
When it comes to storage, the Galaxy S2 is miles ahead - we're talking at least 16GB of internal storage (32GB also available, although not widely in the UK) plus 2GB further storage on top of that.
Compare that to the 1.5GB of internal storage of the Sensation, and you can see that HTC is lagging behind - and the Sensation isn't the first phone the company has done this with. While it's mostly fine when it comes to media, as there's an 8GB card onboard, if you're downloading tonnes of applications then you might fill this up quite quickly if they can't be stored on SD card.
It's a tricky one to call this, as we've been looking forward to the battle between these two dual-core wonders for so long we weren't sure we could decide which was more worthy.
Over the course of this test we've gone back and forth over which to plump for, as both the Sensation and the Samsung Galaxy S2 have a cracking set of features with gorgeous hardware for all kinds of phone connoisseur.
And while it is ridiculously close between the two devices, we think the Galaxy S2 is the overall winner, thanks to its combination of improved connectivity, slimmer chassis and superbly clear and bold screen.
That's not to say the HTC Sensation isn't a great phone too - we love HTC Sense 3.0 and the additional functionality that the improved UI brings, plus the larger screen has the highest resolution of any HTC phone thus far.
So we're crowning the Samsung Galaxy S2 our victor in the battle between the dual-core heavyweights, but if you've already got an HTC Sensation winging its way to you, don't despair as it's a very, very close second.