I have it on my second hard drive (got it off MSDN, as a note to some of you little cheaters.
I, like most, am not overwhelmed. Yes, I built my computer a while ago (P4 1.8, 256 MB RDRAM), but I'd expect Microsoft to make it at least bearable on a computer with my specs. It's a slow hog. The visual improvements are none that really make people jump out of their seats, yet MS really loves filling up those CPU cycles.
I'll reserve judgement, as it is the first beta, however.