I'm using webRTC for a video chat project that I'm developing now. I had a hard time making it work on iOS browsers and ended up supporting iOS Safari alone. Though all iOS browsers use the same WebKit, Apple still reserves a few things only for Safari I guess (maybe H264/VP8 video codec related stuff?!).
It may take some time for webRTC (or Apple) to get there, to webRTC become a solid option for p2p video communications.
If anyone wants to quickly try webRTC, check this demo https://appr.tc/ out, you know, with multiple browsers/tabs.
ps: I used "simple-peer" library and it's quite good for beginners.