I just upgraded from Vista Home Premium to Windows 7 RC and have a few problems with it. RealBand and BIAB work fine but I have problems with my hardware drivers even though they are all Vista drivers. Here is a summary of my findings:
1. Edirol FA-101 Firewire Audio Interface - Their Vista ASIO driver is not compatible. If I try to uninstall and reinstall I get an error message from the Edirol installer that it is not compatible with the Windows version installed on my computer.
2. Sound Reality ASIO driver for Sigmatel Chipset - The device manager shows that the driver is ok but when I try to use it with BIAB and RealBand both give me several error messages including cannot setup buffer. I tried to get an updated driver but found that the Vista driver I have installed is the latest. ASIO4ALL is a workaround for the Sigmatel chipset. It works fine.
3. M-Audio Midisport works fine with Windows 7. I have that connected to a Ketron SD2.

I have a Sony VAIO Notebook with a 2 GHz DuoCore with 4 G/RAM. When I was using the Edirol and the Sound Reality ASIO driver for the Sigmatel chipset with Windows Vista Home Premium then BIAB and RealBand worked perfectly with either setup. Microsoft claims Vista drivers should work fine but that doesn't seem to be the case at least with some audio devices. Also frustrating is that there are some known incompatibilities with the latest version of Skype (Windows 7 gave me this message when I reinstalled). I was able to reinstall and it seems to be working so far but I haven't really tested all the functions. I sent Edirol technical support an email and I will post here the results of their response.

AMD FX-8350 4.6 GHz, 16G RAM, solid-state drives, Windows 10, Scarlett Audio Interface, 2021 BIAB & RB, FL Studio Producer, Studio One Producer, Melodyne Editor, Ozone Advanced.