I've just recently installed Vista for the first time - I never even looked at any of the Betas, CTPs, or RCs. I guess I'm getting old (turned 35 yesterday, in fact), since I no longer leap on beta technology like a pack of starving hyenas on a wounded wildebeest.
So far it's going pretty well. I'm not sure I much like the new UI features - I find Glass to be a bit too, well, glassy. If I want glare I'll point my binoculars at the sun (good gods I *am* a cranky old man) . But I'm going to leave it on and see if I can get used to it.
One hitch I hit was stupid, but I'm guessing that I won't be the only one to hit it. I installed IIS7, and then spent the next half hour trying to find the management application. I located the (awful) command-line tool, but couldn't find the inetmgr.exe GUI. Then I went back into the Windows components installer and realized my mistake...there's a separate checkbox for the management tools that I hadn't checked. Oops.
Anyway, you've been forewarned. Unless the reason you wound up here was you had the same problem and are searching the Internet for the solution. :)