I've been seeing how well Rivet and my wireless router do on streaming video. So far, I've had no problem streaming standard definition TV shows from iTunes - they've all worked just fine, with no stuttering issues. However, I also tried ripping one of my DVDs with Handbrake, using its PS3 settings. This resulted in a 2.1 GB file (just for the main feature). But for whatever reason, streaming this file gave me consistent stuttering, enough to make it not watchable.
So, I don't know if this is a limitation in Rivet, my wireless router, or the PS3 wireless client (I haven't tried running an Ethernet cable over from my router to the PS3 - that's a longer run than I have cable for). I'm going to play around with some other Handbrake settings - there's enough to tweak in there that I'm sure I can find a good balance between video quality and "streamability".