Well said Don.
I have been Yamaha arranger only for at least 12 years and just lately switched to the new Korg Pa900 - two totally different OS's, but very similar things to be done with an arranger are done pretty easily either way for me.
I do have to say I think Korg has captured the market for me as far as blending the Touch screen with the OS.
For me - all manufacturers fall down because they do not print a menu tree for their OS where you can just look at the tree and know where stuff is on that tree - I always have to make my own and then everything falls into place instantly.
Bill G