I own this phone and have done since it was released. The battery life is a problem, however the is an upgrade which apparently makes a big difference to this (although I haven't installed it yet).
I agree fully on the lock button issue. Sometimes it unlocks quickly and others it just takes forever. It gets itself into a tizz and you have to wait a couple of seconds for it to figure out what it's trying to do.
But other than that, I absolutely love this phone. It's hard to state what I love about it because people naturally only focus on the negatives, but it has been a major step up from my last phone (sony ericsson p1i). It is a nice and responsive phone, certainly a step up from the G1 in terms of speed, and its large amount of disk space means I haven't run out yet, and nor to I see myself running out in the phones lifetime. The music player is actually very easy to use - I don't understand the reviewer's gripe here. Essentially this phone has replaced the hair tearing moments of my last phone with moments of true delight, like when today I discovered the phone can actually work as a rudimentary metal detector!