The HTC One S is the best phone on T-Mobile and one of the top Android phones overall for any of the four big carriers. Both AT&T and Sprint are releasing versions of the HTC One X, which has a bigger, higher-resolution display and LTE connectivity. Hopefully the call quality issues I experienced with my test HTC One S are an isolated incident. Phones can do a lot more these days than simply make calls, but call quality remains an important element to consider when buying a smartphone.