I use Win 8 x64 and Sonar Producer x64. They work fine. I use a 6 year old laptop. I disable my video driver, my battery and my wifi card before recording, but I don't get any glitches if I take those steps. I am not able to record at 88.2 and use the TH2 Guitar Amp Sim. I have to stay at 44.1 or 48 if I'm using that. Otherwise, I can hang at 88.2 for a lot of work. 24 bit.
The one change in this version of Windows I've been slow to adapt to is that shutdown is now just another version of sleep (unless you go to lengths to change it). This means that if I leave my M-Audio interface plugged in when I swing the lid down, I'll get a crash when I lift it back up. No problems if I unplug or turn off the device before shutting down or sleeping. But, I'll say, I have been long used to restarting my PC and having a 'soft shutdown' bugs me a little.