Overall, though, in terms of smoothness and snappiness, you won't find a better-performing Android phone on the market today.
The One S is easily the best smartphone available on T-Mobile today - nothing else comes even close. I also think it's currently the best Android smartphone in the US. Not just because of its amazing design and build quality. Not because of its blazing-fast S4 processor, its laudable battery life, or its class-leading camera.
It's a great phone because all of these things have come together in one device. I can't think of another Android phone that has ever brought this level of fit and finish (and most importantly, usability) to the market, and I can scarcely imagine buying something that doesn't meet the expectations the One S has shown me I can now have of a smartphone.