I just tried out Zumocast for streaming video from my Mac to my iPhone. I think the software may be a little wonky (had the phone crash after using it), but I have to say that the picture looks quite a bit better than the one I get with Orb, particularly when I'm in the house on wifi and outputting the video to my TV (using component video adapter) with TVout2.

The files I was playing were AVIs ripped from DVDs, located on a second Mac networked via ethernet, no less.