Sounds like you'll fit right at home.
I'm about to take the plunge from an awesome physical QWERTY keyboard (the 5-row G1 keyboard - best I've EVER used) to a virtual keyboard and I've had the same concerns. However, I'm MUCH less worried now that I have tried Swype out on my G1. It's really good for 90% of what you type, and the other 10% of things aren't that bad. Like anything, it definitely takes some getting used to. I'm still only about 50% as efficient as I am on my QWERTY keyboard, but that's with 2 years practice on it (I can literally type an email while driving with very little eye contact with my phone). But I still have to admit, it will never be the same...
Android in general, though, is pretty good with text entry, user dictionaries, and such. Swype is too.