They're saying essentially Windows 7 is a debugged VISTA.
The real mistake they're making is keeping 32 bit support.
I really thought I'd dislike Vista with all the hype it got, but after using 64 bit Vista for several months now I'm actually impressed with it.
Things like having a lot of applications open and switching between them are much smoother (helps too I have 8 gigs of RAM in the box), and tossing aside instability from playing with overclock settings the system hasn't crashed one single time.
I believe most of the negatives come from the people running 32 bit systems without much RAM, or older equipment. But 64 bit on a new machine is great, and programs that take advantage of it are great too.
Now I can nitpick the stuff I don't like compared to OS X (usual stuff like non static menu bar for applications, etc.) but there is stuff too I think OS X could improve upon.