I can say one thing... i downloaded the latest beta of longhorn, so far it is worse than the very first alpha version of winxp"codename windows whistler"
It is dead slow, the sidebar leaks memory like he*l and the gui itself use ALOT of ram, you will need atleast 1gigs of ram to run it "properly"
m$ acted the say way even with millenium before it was released... One positive thing though.. the included IE had popup blocker and download manager.