Ran my first session tonight - was finally able to get a group together. Players were mostly local (New Hampshire) but we had one from out of state who had no issues.
Everyone was able to login to the Roll20 client, but I had one player whose browser kept crashing every time she tried to enable video or audio. (My wife, in fact, who's in the same house as me, so I know it's not the connection). Based on the troubleshooting, it appears to be a problem between her computer and TokBox, but I have no idea what the problem might be.
I did see above that they're having problems with some camera drivers. She has a Logitech Pro 9000, and I wonder if the drivers for it are causing the problem. I tried having her update them, but to no avail.
On the bright side, we switched to a Google+ hangout and were able to play with no problems. The integration with Google+ is really very impressive.
The actual play-test went exceptionally well, but I'll save that for another post.