Justin trends down as Ustream begins its ascent
alexa.com
alexa.com
I think Justin.tv's problem is the scaling. The cutting out isn't too bad, but once they hit 400 viewers it starts to becoming a pain to watch.
But that's OK for justin - because their business model is to sell this solution to others, and they've already proved it works.
On the other hand, Upstream is more of a social network type site that takes facebook stalking to a new level. I envision people using it to keep tabs on what their friends are up to. Who knows if it'll work, though.