Just found an interesting video on YouTube comparing the 360 to the 505. What caught my attention was the control button on the 360 does make an audible click when pressed. That might be a bother to some people. I wonder of the button was chanced to a tactile-click only (as in a silent button) in the final production model?
http://www.youtube.com/watch?v=PcRna0NtBZM
(it's a short 1-min video)