I hope I am not one of the few who didn't like the interface. It looked too much like "flash interface" you see on some websites. Not a big fan of sideways sliding.
I applaud having more choices in interface, but I am more interested in better choices as opposed to having just another choice. Hard to draw any solid conclusion just by watching that video, but not very impressed so far. IMO YMMV
You won't be the only one. However, I know a lot of Zune owners (mostly that won them, not bought them) that thought they would hate the interface and ended up liking it a lot. I don't know if I would like it until trying it. I thought for sure I would like the iPhone UI but it often drives me crazy.
I applaud having more choices in interface, but I am more interested in better choices as opposed to having just another choice. Hard to draw any solid conclusion just by watching that video, but not very impressed so far. IMO YMMV