Yep, Chony, those Mega voices are the kicker.

They require a LOT of work to make even the played notes get over to another arranger, and forget about all the associated noises, chokes, etc..

It's a whole patented technology, and, in all honesty, I have never heard a Mega voiced style sound as good on another arranger. Drums, horns, pianos, etc., no problem (much!) but some of the styles use Mega basses, and even a lot of that doesn't translate that well.

Personally, I'd take a look at whether you can get the PAX to sync to an S900 or 700, and combine the two. If those Mega voices are important to you, there's no getting around it. You have to play them on a Yamaha.