Several reviews mention that the the S4 is sluggish compared to the HTC One. I was in the AT&T Store yesterday and did my own testing by restarting both phones to get to a fresh slate, then opening up different apps simultaneously. The first one I did was Facebook. On the HTC One, the app opened and the login screen appeared nearly instantly. Meanwhile the S4 was still loading the app, several seconds later the login screen appeared. This type of lag was consistent across multiple tests I ran. I really like the HTC One, for many reasons, including the fact that it runs much more quickly, however I ended up ordering the S4 because it has the superior camera, which is very important to me (again, that statement is based on several reviews I've read and looking at a lot of pictures taken on both phones). I'm somewhat regretting getting the S4, but I am hoping that there is a way to disable some of the bloat on the S4 without rooting to speed things up. The S4 has the faster processor, so the fact that it runs slower in real life I attribute to the fact that Samsung has so many stupid features baked into the phone. Perhaps it's something else, but whatever it is, how can I get the S4 to operate as quickly as the HTC One?