I've had one for about a month. The battery life was very bad at first, but then I twiddled with the settings about stopping certain apps from running in the background and now it's tolerable
I just leave airplane mode on all the time and have a short screen timeout. I also use wired headphones. It's certainly usable as an mp3 player. The extra functionality is a bonus that I very occasionally use (I have a cheap sim card in it).
