I would really like to use the 64-bit version, but the fact that you can't do an upgrade, only fresh installs, will keep me away until I'm ready to rebuild my system.

Dual-booting is senseless between two functionally identical OS's (and I'm a little low on HD space right now on my C: drive).

I was uber excited for this to come out and now that it's here, it still seems to be lacking some things, so I'll hold off for now.