I was really excited about this extension. It is extremely powerful. I am a little disappointed that you can't use ustream. The church I am working with live streams their service every week. The only way I can use this extension is to have them use ustream (for their live stream) and vimeo for their channel. That's a little too much to ask them to do. That's the only reason I can't use it. So disappointing as this is a powerful extension.
Thanks for the review. Yes, you are right that Preachit doesn't support ustream out of the box. However, Preachit has a custom mediaplayer engine that allows you to add other mediaplayers to the selection. With this it should be fairly easy to get ustream videos to play within Preachit.