It's definitely out and I've been using it for about a week now.
Things that I like:
Enhanced freeze funtionality. I haven't had any problems with this new functionality. You won't hear that story at the Cubase.net forums though.
Color coding of tracks.
In place editing. This has worked fine for me, but some users report problems when adding in notes, etc.
It's been running solidly for me and I don't find it totally "unusable" as many other users seem to. I actually haven't really experienced any show stopping bugs yet, and I didn't in SX 2 either. FWIW, Steinberg announced that a maintenance release is coming in late November and truly seems focused on fixing old problems and any new ones that pop up.