I'm no techie, so I don't play with stuff to well after they are released and bugs worked out. However, my local chase buddy is one of the tester people that gets each release like way early (even says they are done with Win7 and starting to work on Win8).
We used his laptop with Win7 on it and hit did well. There are a few features that seem to make life a little easier for switching between windows. It ran smooth during chases, including streaming, GR2AE, looping sat., chat room, and tons of more windows open. It does seem to run better.
Techie folks always love new stuff, almost to a fault. I still will not use "Seven" until it's available off the shelf, and likely not until Service Pack 2 (also under development I'm told). I've used this philosophy since starting with computers in the 80s and haven't had hardly any issues the past 25(+/-) years.
Edit/add: GR3 also worked fine. All this was on a Lenovo (formerly IBM)