The battery life on the phone is shit, but since I only needed it for music, I could do something about that. I rooted it, added some automation: automatically launch music player and scrobbler on startup, activate airplane mode except when plugged in, add sshd service so I can rsync files to it, and turn the device off if music issn't playing for three consecutive checks (each 15m apart)
The only thing I need was a decent music player. I tried Musicolet, but it didn't suit me. For a start, it just doesn't work well on a small screen. Almost every piece of text was truncated. I also found that it didn't pick up media changes a lot of the time (eg sync a new playlist). I ended up going with phonograph because it's perfect on a small screen, has good controls and is really simple.