I've installed Vista by myself countless times since the first beta builds, and I haven't had much problems with them. Usually I just tested it for a few days and then removed (and I seem to be the only one who uninstalls Vista by deleting the directories instead of formatting the partition).
Now I'm posting this from Vista as well (about to boot to Linux though), it runs fine, this feels somehow more tolerable than XP's default UI and behaviour.
The few games I play work just as well as in XP - I don't care if some 3DMarks get a few hundred lower or higher score. No problems with Nvidia's 158.18 drivers, either. DirectX10 and the lack of hardware 3D sound in games don't mean much to me.
So far applications I've installed have worked. Sometimes that compatibility wizard pops up after a successful installation, thinking something didn't install correctly (usually a Nullsoft installer).
I do miss the horizontal scrollbar on Explorer's folder view on the left, that automatic moving is irritating. It also refuses to remember the window size.
Aero Basic or Glass window colors can't be configured except for the few colours it allows me to select - the classic control panel has little effect. I got the border padding off, though.
Naturally, Microsoft has moved or renamed a lot of options and applications (customers want to learn things again with a new OS, right), but I'm beginning to remember most of them. The classic start menu and control panel help there.
Of course, I have tweaked Vista a bit, manually and with
X-Setup Pro, and I customized the installation image with
vLite, removing unnecessary components such as music and movie clips, printer drivers etc.
Oh, I also don't use that 3D thingy that seems to be in every Vista screenshot, I removed it from Quick Launch bar and I simply don't have Windows keys on my keyboard. Alt-tab does the job for me.
I won't cry when Vista uses more RAM than XP, either - even though it only sees 3 GB of 4 installed - or when it has more processes running (50 processes at the moment, about 1.2 GB of RAM used). It just happens to have more features. I don't really see the point buying a fast computer and then complaining that it's not idling, but that's just me...
And about 15 years after Windows 3.11 for Workgroups, I still can't rename the network or join another without rebooting, or change the system locale without rebooting...