I use appear.in every day. 1-click video chat with no account sign up. The ease of launching is what keeps me coming back, even though it seems a little buggy now and then (which might be the early WebRTC support, who knows).
I actually used this a couple days ago for an interview. Cool stuff. The UI needs work, but functionality wise, really impressive. The quality was great and there were 3 people on the call. I'm not sure how it'll handle much more than that, but it worked great without any hiccups.
