I've had one since April. There are a lot of good things about it, and I have learned to really enjoy using it. There is some craziness with the way it handles some wi-fi access points, and certain apps (e-mail) can be slow at times. Sometimes programs crash, maybe due to memory problems (once again, it's the email)? Also, as someone who uses a NAM version, it's frustrating to be several months behind on firmware.
It does have really good speakers on it. One minor gripe I have about audio playback is that the default player doesn't have gapless playback. You can find apps that will do that, but it's not quite as convenient.
It helps if you have small fingers...
All in all once you get to exploring some of the s60v5 apps out there and play with it, the 5800 can be a pleasure to use. And the AT&T plan with unlimited data I've seen is only $15, so there you go, $120 more of the next 2 years to spend on something else