I purchased this phone to replace a blackberry with medical software and an MP3 player. I wanted something that would fit into a woman's pants pocket with ease, and this certainly does. I don't go online much to check email or browse the internet, so screen size wasn't so important to me. It runs Android well and Epocrates beta for Android works as well, if not better than epocrates for blackberry, which I used to use. It has a headphone jack and a fairly exceptional built in speaker (considering the small size of this device). The audio quality for MP3 playing is excellent. The camera is fine, but doesn't replace a point and shoot for special occasions. Texting with the built in keyboard is fairly easy, but I am not a big texter, so I can't comment much on that.
I am pretty rough on my devices and have dropped this on the floor many times, and also recently submerged it in water for about 5 seconds (toilet bowl mishap). It has never malfunctioned despite my abuses, and actually looks really good after many months of use.
Usability as a phone is fine, although the screen turns off after a few seconds to save battery, so I have to "wake up" the phone again to end a call.
Battery life is fine for my uses- needs charging every 3 days or so. Probably would need to charge once/day with heavy use.