Mixed feelings from those videos for me. General style is in some ways nicer than the PS3, but also goes a bit overboard with gradients, etc in places. Are some good design choice on spacing and margins (which make the errors more glaring). Navigation wise... hard to judge from just a video, but it looks like it needs more consistency between the various sections. To be honest, it'd take a lot for it to be better than the PS3's XMB for me.
UIs should be judged in use though, not from a video or screenshots. A pretty UI means nothing, nor does a messy one. I've got software on both my computer and phone that I use not because they are the prettiest, but because they do what they do best.
Speed and the ability to do everything whilst in-game are all that's really needed over the PS3 XMB IMO. Both things are included now.
Voice navigation, logging in with a camera, move gestures, all of that crap I can do faster with a controller. I've only been using either a kb/m or controller since the early 90s. Call it being stubborn to change if you will, it simply works fastest (and 100% of the time / motions & voice can be finnicky) for me.