I've had one of my machines manage to stay on for around a months (pre-RC1 code)...now thats pretty good considering we've been using it for gaming, modelling, watching movies and all sorts of stuff.
It's meant to bring the compatability of win9x to winNT, and it does, quite well in fact.
There are a few bugs with it...only a few though

It's not finished yet, so for beat code, its pretty neat.
Overall, this will prolly be the best OS by Microsoft.
(btw, if you are annoyed by the design of it, you can change it to the 'standard' style as in win9x or 2k)