Last night, played a game of Savage Worlds. It was a little tough. Four players. To are off-site, both running PC and Firefox. The GM and third player are on the same site (both using the third player's wi-fi). GM and third player are on Mac and Firefox. Long story short, we kept losing audio and visual seemingly at random. Eventually, GM started getting booted once every five minutes... logging in was a snap, so we struggled through it for a while, but eventually it became too much. Love roll20, but we were spending more times dealing with technical difficulties than actual gaming.