I got the Galaxy S in February. On the whole, I love the phone. Screen is very responsive, nice and bright, and all the menus are very intuitive and easy to use. The battery life sucks, that much is true, but it's nothing a nightly charge doesn't fix.
There are a couple of things bugging me with it though. I have to reset it (battery and sim out etc), once a week almost, due to not being able to get on the net. I am not going near any settings at all, so I've no idea why the Internet connectivity is so erratic.
The other is the music player. On a few occasions now, each time I've tried to some tunes every song is accompanied with a message saying that this type of file is unsupported. Which is rancid nonsense. Again, the only thing that seems to rectify the problem is a switch off, battery out, sim out job. Which is a proper pain in the hoop.
As I say, I love the phone, and it's the best phone I've owned with regards to it's capabilities etc. In no way is it the most reliable though.