First off, they are in fact great phones. I find new uses for mine all the time. They have tons of apps to choose from in the market, lots of "fine tuning" you can do.
As paul said, the battery is the worst part about it. BUT, there is a app that cost like $3 in the market that will help you out on that. It made mine last several hours longer. (it just disables the extra stuff on the phone you probably won't use)
As far as the bluetooth functionality, the only thing I've tried to use mine for is to sync up with my car radio, and it does that now after the cupcake update. So really I have no quirks there, but I don't use bluetooth besides that.
The camera would be the other bad thing about the phone IMO. It doesn't take the best photos. But I have a nice digi camera anyways, so that didn't matter to me.
Honestly, I've played with a lot of the phones on the market, and nothing was as "snappy" and responsive as the G1's GUI. It is really smooth, much better then any windows mobile OS I've used. I personally like the way the menu/settings is setup. It's pretty streamline IMO.
All in all, the only phone I'd probably trade this in for is the HTC touch diamond, or the G2.
