From a usability perspective, this is 10x better than what it used to be. I'd still make Search the first option on the 2nd roller and allow access to YouTube accounts but hey.... I can wait a little longer for that :-)
The main problem with this feature for me still is the playback performance. Now, I don't have the fastest Internet connection in the world but I can still play higher quality content with some buffering in a browser no probs. In tview however, playback stalls constantly with no visual feedback as to what's going on. For all intents and purposes it looks like MC has hung and in some cases, it will, requiring me to kill MC via taskmgr.
I've also been able to make MC hang on several occasions by pausing and/or jumping backwards and forwards in the video via the on screen display (left & right arrows).
I love being able to watch YouTube from the couch on the big screen and we're getting so close now..... A little more visual feedback and some tweeks to the buffering strategy and I think we have a winner!