The version for the Wii streams the video as it converts it to a Flash 7 player that Opera uses on the Wii. Far from perfect, but I was very impressed for what it was. I am sure it will work a lot better on a 360 or a PS3 though.
The video would make a very slight stutter here and there and the framerate wasn't perfect, but for real time video encoding to an obsolete flash player I was impressed.
For streaming something to the Wii, I would have to give it a 8 out of 10. There is a lot of room for improvement, but they have done a LOT with the limited resources available to them.
The great thing with the PS3 is that you can still use the media server functionality on the PS3 while using remote play on my PSP. So I can watch my movies and music anywhere (as long as I have a wifi connection).