I tried both this and Tversity today. I couldn't get playon to stream files from my pc which is what I wanted more than streaming from the net. Tversity does this but it's really slow and needs to load every couple of mins.

I really just wish Microsoft would open up to more formats. It would make the 360 actually useful as a media hub.
Of course then they would lose a lot of money for their on demand movie service. Bastards.