I asked about Sensei in another thread, I guess you didn't see it, and got about the same replies.  I personally use it, and it's been the one thing that's really helped me get along well with Blender.  I don't know, I think the UI is just much cleaner, and the drag n drop ability it has makes it very cool.  I know people will say Blender standard already has everything that's in Sensei, but I think the way it's customized and laid out makes a big difference.  It does make it harder to follow standard Blender tutorials though, because of the hotkey differences, but once you get used to that part, it's cake.  I mean, it's hard following an older tutorial for Blender standard, because before 2.6, there were a lot of different hotkeys too.  So yeah, I like Sensei.