Note: Our original review was of the unlocked, GSM One S. We've updated the review with impressions and tests of the $199 (with contract) T-Mobile model as well. Check out the Hardware, Connectivity and Software sections to see the biggest differences between the two devices, which are generally quite similar.

When I first saw the HTC One series, in that top secret subterranean bunker where HTC likes to preview its phones, my attention and desire were immediately drawn by the One S. I didn't care about the 4.7-inch, quad-core One X and its supposed flagship position, I wanted to know more about its 4.3-inch ultrathin brandmate. That’s no knock on the One X, which ticks all the boxes for a legitimate Galaxy Nexus competitor, but the 7.8mm thick One S offers a much more mainstream form factor and price point, while also being the thinnest smartphone that HTC has ever made.

That sort of instinctive reaction is exactly what HTC is going for with its 2012 range of Android phones. It doesn’t want customers to think of distinct tiers of devices, it’s trying to pitch us options A and B — or One X and One S, in the company’s vernacular. Sticking with the theme of singularity, however, most buyers will only have the budget to own one Android 4.0 handset, so which One should it be?