The issue I had with vista was SPEED. I think it was just my computer but boot up time took forever and a day. I timed it once and it ended up at being over 5 minutes!! When I got this new PC I booted them up at the same time and I was on this once browsing the web and listening to music before I could even see the desktop on the old one!
Admittedly, I had never got around to clean installing vista as
a) I really couldn't be bothered to go through all the hassle and
b) By the time I knew how to do a clean install properly I was almost ready to by this. So I didn't clean reinstall vista.
And before you say anything, I went through every method of speeding it up and none worked on it.
In comparison, I can open firefox in less than 15 seconds from a cold boot. On the old one, it took about 1-2 mins! I know it probably wasn't all vista's fault, probably mainly the PC but from that I have just not enjoyed using vista. That is why I rate it as bad