Version: 10.10 (just released) Mac Pro: (Early 2009 quad) GPU: AMD HD 7950 I'm using this as a test bed for Yosemite before I put it on my new Mac Pro. I've also been using the preview Yosemite on a laptop and it's been fine with essentially no glitches detected. So far it seems just fine, other than a few incompatible plugins. Nicely they warn you about this right after install now Wacom Control Panel plugin and driver (auto uninstalled) GPGTools One other, darn it I forgot. Some interesting things The GPU fan is better controlled now. Quieter - I can't hear it at all whereas before it was slightly audible. Safari is more 'hinky-jinky' while typing in text. Can't say whether that's just the web pages I'm on or Yosemite yet.