I am planning to do a review of Secondrun.tv as soon as the product becomes a little more stable. Right now Jason is working through some bugs. What I can tell you is he has received over 4000 downloads since he posted the first beta builds on Friday. Obviously this points to quite a bit of interest in getting Hulu and other online TV into the Media Center UI.
The next step will be figuring out how to real-time transcode this flash based content to something such as WMV, so you can watch it on the XBOX360.