what is p2p performance like? what amount of code would have to be written?
For WebRTC p2p video streaming in general, it seems promising. At the moment, though, there's little to no browser support and getting a full system (there's also a server involved, to initiate the connections) is not automated or abstracted yet.
For more info, check out this page: http://www.webrtc.org/running-the-demos