Well, I am running Windows 7 Beta (build 6801) on my desktop PC at home, and I must admit that I am impressed with it so far. I only had one blue screen of death so far, which was caused by some TCPIP stuff, I rebooted and its been stable since.
I skipped Windows Vista on my desktop, been running it on the Sony Laptop since August sometime and I must admit I am even more impressed with Windows 7 as it seems a lot faster.
Initial tests show that the system boots the fastest on Windows 7 than on Windows Vista (2nd) and Windows XP SP3 (slowest).
More to follow as I play around with it some more