Beta is running on laptop at work (ok, all has been provided by M$, so I presume they selected the hardware they knew as fully compliant..) and honnestly, it's nice looking. The Aero thingie is really really nice and it seems demomakers were around (yeah since it's really nice to look at..). Now, honeslty, I don't give a f*** about windows poping etc when working. It sounds like piece of toys to me.
I'll have it installed within a few days here (i hope, matter of time to be honnest....) and i'll have a closer look: its fonctionalities and not its look.
About the beta thingie and most of you hesitating to install it (i can understand), you may consider the "virtual machines". It's a good idea to have different os. Of course, it won't be the same (except if you have one of those HP blades with 8+ cpu and 4gb ram @ home...) but it can give an idea.
And the good point is the virtual software: beta is open @ vmware, it runs fine here