I was pretty stoked for appear.in but found the voice quality poor and the screen share awkward. It's a brilliant concept but it seems like WebRTC needs some optimizing before it can compete with skype or hangouts.
I've not had any problems with voice quality; I know what you mean about the screen share though. I think that's to do with Chrome only grabbing a low-res feed from the desktop, from what I gather from the appear.in dudes & dudettes on twitter.
