I'm a beta tester too, I think it's OK, although it does not run well on older systems unless you kill off all other tasks (no minimizing your Firefox with 27 open tabs, sorry!). And the content is neither terribly extensive or updated as often as it might be.
Just the same, if you want TV online, the only real choices are Joost and TVU, and Joost is more bandwidth-friendly (as well as probably more legal). In my area, there is one station which I can pick up very badly, and that's all. I refuse to pay for cable/satellite anymore, when I only watch one or two stations occasionally, so... Joost and TVU are enough for me.