Oh i can weigh in on this big time.
FUCK VISTA. it is not ready AT ALL.
If you are just a guy with a 'puter, sure vista is fine. but if you do anything beyond surfing the net, wait a while. Most software has some kind of issue under vista. I turned off the stupid security features because it was just getting so annoying. My virus software didnt work (though it supposedly does now). Photoshop CS2 kinda runs like it should be wearing a helmet, and not because it plays sports... Even something as simple as CuteFTP didnt work right.
most of the problems are security related when it comes to software.
hardware... ugh. drivers are non-existant for anything but mainstream stuff. even my brand new DELL had driver issues. even with the VISTA drivers they released. LOL
telnet is gone as well.

(though you can get it, but its not in the installation)
I have Ultimate, and it has media extender capabilities built in, so my xbox360 can play movies. or not... depends on how the gremlins feel that day.
The file structure is a little changed, for the better, but not worth the upgrade.
interface... meh its a computer desktop.
sidebar... turned it off cause it kept crashing.
animated desktop... hey cool, im bored now.
new Alt-Tab thingy... OK this one wins for me. I loved it. but not by an stretch enough to justify the problems.
general operation of it was fast. but then again, I have a 4gig 2proc core2duo box. but it did seem faster than XP. I did not have the slow boot times people have complained about.
the bad part is, that early adopters really shouldnt upgrade. Yet, people like my mother and father probably should. it would protect them a little better. For me though, and probably most of you, the security features actually increase the danger. I spent so much time clicking OK,Yes,Sure,WTF,Whynot,Go,Approve,Whatever, that frankly if something popped up and said "hey, can i fuck up your computer" I probably would have clicked YES without realizing it.
It was overkill.
There were quite a few nifty things to play with, but that does not make a good work environment.
wait till SP1 for sure.