I've experienced a few crashes so far, but some of them were related to the fact that I was pulling massive amounts of data for the restore, so I let them slide.
All in all it's pretty stable, but still obviously beta software. Beta means beta. I don't understand why people assume this is the release version. It was specifically beta'ed for the EXACT PURPOSE of finding bugs. Everytime it crashes, Apple learns something they didn't know before.
With that said, I've noticed a little weirdness with iTunes Match and music, sometimes it signs me out whenever I log into my iTunes/iCloud account with the other AppleID. My iCloud Email and AppleID are different (however interchangeable in everything). Weirdly though, iTunes Match does a MUCH better job of actually working in iOS6 than it did in iOS5. Apart from being signed out twice, which wasn't a big deal, I haven't been able to trip it up.
Seriously though, there are new features EVERYWHERE, and most of them aren't publicized.
Read the release notes over at the Dev center. Cool stuff they fixed/added.