I've got 7 on both my desktop and tablet (got the copies through my school's MSDNAA program -- if you're in college, see if your school is participating in it -- you too could get 2 free copies!). I'm really liking it so far. I've used win2k until about 2007 and then I've used XP the last 2 years, but I've really gotten used to 7 over the last month or so and I haven't had very many problems with it other than trying to get some of my old games to run.
Someone asked about the tablet handwriting recognition. It actually works pretty well for when I'm trying to look up a kanji - I can badly scribble the kanji and it'll still recognize them fairly accurately saving me from having to look it up by strokecount or radical. My tablet is fairly slow though (1.1ghz pentium M) so the english handwriting recognition is much slower. I'll end up writing 2 words before the inking appears on the screen since it's trying to crunch what I'm writing as I'm writing it.. it's pretty annoying so I don't use it much.
