I've been running Vista for six or seven months now, a few teething problems, all overcome, and basically it's running sweet as a nut.
But.
I have 4 computers and only run Vista on one of them, the main reason being DX10 for gaming.
I bought Vista Home Premium OEM for £65.00 mostly cos I was curious. And I do actually like it.
I also recognise it's flawed, it is a resource hog and it runs slower than Vista on some things. Only on some things though, on most usage it's as least as quick as XP.
But, all in all, this far down the line I have to say I really like it.