Running the three handsets simultaneously, we found that the iPhone's display was slightly crisper and colours were a touch more vibrant than on the One X+ and Galaxy S3.
That said, the difference is minor and we only noticed it after closely comparing all three screens. Ultimately, all three devices have great screens and most users won't notice the minor difference in quality unless they really look for it.
Winner: iPhone 5.
All three smartphones are very powerful, with the One X+ packing a fearsome quad-core 1.7GHz Nvidia Tegra 3 processor, the Galaxy S3 a quad-core 1.4GHz Exynos processor and the iPhone 5 a dual-core A6 chip believed to be clocked at 1.2GHz, but uncomfirmed by Apple.
Unfortunately there's no reliable benchmarking tool that works across both Apple and Android smartphones, so we couldn't accurately compare the three devices with benchmarking tests.
However, racing the three handsets against each other we found that the HTC One X+ was the clear winner, loading web pages, streaming videos, activating and responding to commands a fraction of a second faster than the iPhone and Galaxy S3.
Winner: HTC One X+.
The Galaxy S3 and HTC One X+ both run customised versions of Google's Android mobile operating system, while the iPhone 5 uses Apple's iOS 6.
Comparing the two Android phones, the Galaxy S3 is a generation behind at present, running Android 4.0 Ice Cream Sandwich, overlaid with Samsung's custom Touchwiz user interface (UI).
The newer One X+ runs Google's latest Android 4.1 Jelly Bean release, overlaid with HTC's custom Sense UI.
This means that, although Samsung has begun rolling out an Android 4.1 Jelly Bean upgrade for the Galaxy S3, it is still a release behind the One X+, which counts against it as Android 4.1 Jelly Bean's new features are pretty awesome.
Of the new additions in Android 4.1 Jelly Bean, the Google Now service and Project Butter buffering are by far the most useful.
Unlike on other smartphones, Google Now doesn't appear the moment you wake the One X+ from sleep mode, and cannot be accessed by swiping up on the device's Home screen. Instead, the feature is included as a dynamic widget that can be added to one of the devices Home screens.
Google Now delivers a number of dynamic "cards", each containing information the device calculates is relevant to the user, based on information taken from their Google account.
This includes location, search and purchase data. While we'd have liked to be able to access Google Now the regular way, it is still a positive addition to the One X+ and we found ourselves regularly checking the widget.
Project Butter is a more subtle buffering feature that aims to improve the core OS usability by fixing performance problems, like display frame rate issues, that made smartphones running previous versions of Android prone to stuttering.
Testing devices equipped with Project Butter, we've found them more responsive and slicker to use than their Android 4.0 Ice Cream Sandwich powered rivals.
Finally, the superiority of the One X+ Android version over the Galaxy S3 Android version is cemented by its far less busy Sense UI.
This article was originally published on V3.
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