You may have already invested time into getting set up w/ ustream etc.- np, but since you mentioned this in the other thread I thought I'd respond real quick (:
* There is no pricing, no cost, even if you have tens of thousands of concurrent viewers (we have several broadcasters in that category) at maximum quality.
* We have fewer ads than the others.
* We're mostly oriented around making it a social experience- this helps you because it means the viewers have ways of pulling in other viewers.
* With JTV your stream will be higher quality (measurably) than others.
Check out http://www.justin.tv/broadcast/advanced for options on getting set up- the forums tend to be pretty helpful as well. We can't really help with cameras etc. (a strategic choice)- but once you manage to get set up you'll be absolutely giving the best experience to your viewers.
Hope that helps (: