To be honest, although I've had a touch for several months, I haven't used the keyboard much. I'm doing a bit of practicing now, though, in anticipation of the iPhone. I didn't know about the tap and slide before I read this thread, and part of what was holding me back from using it before was the two-step punctuation process, which I hated, frankly. Thanks, guys! 🙂
Now the biggest peeve for me is the lack of cut and paste, as others have mentioned, but I think it's mainly because we're spoiled from having the full browser, which makes you feel like you should be able to do everything you can do sitting at a regular computer.