I'm using it on my iMac, my main work horse. Seems stable, no crashes.
Notifications sidebar is awfully slow, and Spotlight doesn't appear in the center. iTunes feels clunky. Those are the bad experiences so far.
But of course if you are using build tools i.e. Xcode and co. then I don't recommend you use it, that's usually where it's likely to break things because of updated APIs. I have a secondary machine I run builds when I need them.