why are you guys having problems like this? i'm using 2007 b2tr and its working perfectly! its not quite as fast as 2003, but it is beta software and i wouldn't expect it to be.
I was only having trouble because I was trying to run it side by side with 2003 (excluding Oulook). It worked for a while, then it got frustrating.
Once it started, it ran pretty well the whole time I had it installed. I still needed to do most real work in 2003, though (there's a reason they put "not for production use" in the EULA for beta software).