The comfortable one-handed operation is my top reason, I'm a pretty active person and a phone that I can comfortably use with one hand (and also easily stow in and remove from the front pockets on my jeans) is much more useful to me than a phone that I cannot. I also enjoy the headphone jack which allows me to use any pair of conventional headphones, without requiring an adapter. Finally, the square edges (in contrast to rounded) make the phone a great bottle opener.