Before we go any further though, check out our Samsung Galaxy S3 video.
- Now unveiled - check out our hands on: Samsung Galaxy S3 review for all the latest information and pics on the handset.
Right, without further ado, here's our full head-to-head between the three handsets.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: processor
The HTC One X boasts an Nvidia Tegra 3 quad-core processor (one of those 4 cores plus an extra core type-things) clocked at 1.5GHz. The S3 introduces a new quad-core 1.4Ghz chip called the Exynos 4 Quad, while the iPhone 4S has the dual-core Apple A5. Indeed, the A5 now looks the poor relation of the bunch, despite being a powerful 1GHz dual-core chip.
All are based on ARM's Cortex-A9 design. The Samsung's multitasking performance is demonstrated by a feature called Pop Up Play, that enables you to carry on doing tasks in a corner of the screen while watching a video at the same time.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Design and dimensions
Like the older Galaxy S2, the s a neatly designed S3 continues with a lightweight plastic design and, while it won't appeal to all, it's only 7g lighter than the iPhone 4S. The S3 weighs in at a respectable 133g compared to One X at 130g.
The HTC One X has a new unibody design formed from rather cool polycarbonate (super-lightweight with the ruggedness of metal, according to HTC). As you'll no doubt be aware, the iPhone 4S continues with the glass and aluminium casing we first saw in 2010's iPhone 4.
The new S3 imeasures 136.6 x 70.6 x 8.6mm compared to the One X's 134 x 70 x 8.9 mm and iPhone 4S at 115.2 x 58.6 x 9.3 mm. Yep, it's a biggie.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Screen
This is where the One X and S3 really mark themselves apart. The One X has a 4.7-inch, IPS (no OLED) 720p HD screen (1,280 x 720 resolution) – it boasts a pixel density around the 312ppi mark, compared to the 3.5-inch 960 x 640 retina display on the iPhone 4S which clocks in around 329ppi.
Unbelievably, the Galaxy S3 is the poor relation here (hardly) with 306ppi on the 4.80-inch Super AMOLED display. It's the same HD res as the One X.
The iPhone 5 will certainly have some work to do to catch up when it's no doubt released later on this year.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: OS
The HTC One X comes with the Sense 4 overlay. This includes HTC ImageSense, a new suite of camera and imaging features that speeds up image-taking. HTC says it's ready to take a photo in 0.7 seconds and autofocus in 0.2 seconds, plus you can even take photos while shooting video. The browser in the X also supports Adobe Flash.
As you'd expect, you still get Samsung's TouchWiz overlay in the S3, albeit with a totally new and decluttered look.
Samsung reckons it has been inspired by nature with this release (quite why, we're not sure) but as you can see here, there's plenty of water rippling around. As with HTC with Sense, TouchWiz is one of the key ways Samsung believes it can differentiate itself from other manufacturer's Android handsets.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Connectivity
All these handsets have A-GPS, 802.11n Wi-Fi, HSDPA, HSUPA and Bluetooth 4.0 apart from, surprisingly, the One X, which only has Bluetooth 3.0 (presumably to do with the Nvidia Tegra chipset). All have accelerometers, proximity sensors, gyroscope and a compass.
All three have 3.5mm audio jacks. The One X also features an NFC chip, while the S3 has a barometer. The two Android handsets feature microUSB, while the iPhone 4S has the familiar dock connector.
All the phones support HDMI output - the HTC and Samsung via their MicroUSB ports, the Apple via its 32-pin Dock connector - via adaptors.
The iPhone 4S has Apple's own AirPlay streaming system (including 720p AirPlay Mirroring to Apple TV) - the other two phones are DLNA compliant for wireless streaming.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Camera
The HTC One X, iPhone 4S and Galaxy S3 cameras are all 8MP units with full 1080p video. The secondary cameras in the X is 1.3MP and the S3 is 1.2MP, both capable of 720p video.The front camera on the 4S is VGA.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Memory and storage
The HTC One X features 32GB of internal storage and no microSD card slot. The S3 is available in 16, 32 and 64GB like the iPhone 4S but does have a microSD slot (as you probably know, there's no slot in the iPhone 4S). The HTC and Samsung handsets have 1GB of RAM while the 4S sticks with the meagre 512MB.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Release date
Of course the HTC One X and iPhone 4S are already with us, but we know the Samsung Galaxy S3 UK release date is May 30 2012.
Samsung Galaxy S3 vs HTC One X vs iPhone 4S: Verdict
Well, where to start? Well, with the iPhone 4S. In the age of the superphone it's clear that the iPhone 4S no longer cuts the mustard - especially with the premium price tag it still has. Talking of price tags, we're expecting the Galaxy S3 to be quite expensive when it launches - even if it clocks in at £36 a month, it's still £10 more than the cheapest HTC One X deals we're seeing.
And that's a premium we're not necessarily prepared to pay. The screen on the Galaxy S3 is wonderful, but it's not so much better than the One X that it's worth that extra outlay.
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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.