I wasn't really a fan of joost. It was very choppy for me. All I wanted to do was see some Stella episodes but it kept completely stopping and starting the next one. A friend of mine said it was much smoother in the earlier releases so I'd assume that it'll run nice at some point. I'll give it another chance in a few months.
So is it any good? Seems like an interesting thing at least. Then again, it sounds like TV (which I like) over the computer (which I like) so I guess I'm predisposed to liking it.