I left Yamaha, went to Technics which I really liked (too bad they stopped making keyboards), then went to Wersi which I feel is the most advanced arranger available today. I'd never even contemplate going back especially to Yamaha. If there was one thing I missed on the Yamaha it's not coming to mind. I liked many of the Yamaha sounds but I didn't find them any better than what I was using on the Technics and certainly they are nowhere near the quality of the instruments in my Wersi. Of course YMMV but IMO the Wersi is hard to beat.

Also, I found Yamaha's customer support to be atrocious when I owned my 9000 Pro. Unless Yamaha comes out with an arranger that's leaps and bounds above what I am currently using (Wersi), which isn't likely, I'll never consider another Yamaha purchase again.