Ustream is often higher in unique views (but not always, and not currently), but Justin.tv has people stay on site almost twice as long, and has almost half the bounce rate. It certainly pumps far more video in and out (at one point at least more than even youtube, but I don't think we've measured that in a while). Livestream is a distant third. Ustream spends a lot of money projecting their image, while we just keep making sure that our product is several times better.