I listen those videos even before this post was started.
Even as a fan of Korg PA880-PA2x arrangers, I think that songs and way selected to compare the arrangers does no help any of the keyboards. and is unfair to all of them.
A valid one will be using the a sound system (same for all) in a Live Play scenario.
I think that the same person that post those videos have a set where he compare PA2x and Tyros 3; again of no value for me.
I agree that the solo sounds and styles are the main components of any arranger, but other details like registrations, support, songbooks, dimensions and weight, etc are important components too.