I've been running Vista on my Toshiba Tecra M7 for a while now.  As an office 2007 and email reader it works fine.  I like the new tablet stuff a lot, and in general the OS feels better than XP.  It's been horrible for a development box though. I still don't know if my issues are because of beta drivers, or if they are all Vista related. Here are some of my biggest issues:

• Lot's of issues transferring files over wireless (especially zip files for some reason)
• Power consumption is horrible.  I tried tweaking my power settings and I get 45min at most on my battery
• I Finlay turned off suspend mode. It just doesn't work very well.  I've had issues with hibernate as well, but not as many.
• When the system runs slow, it starts missing keys that I type
• Very slow when compiling code

Development has been so bad that I know usually just remote desktop into my main development box and develop that way.

Toshiba has removed all the driver downloads for the M7, so my hope is that they are fixing some of the bugs and will re-post them once everything is more stable.