Hi Brienn and all others!
I have tried the MZ2000 out and thinking of buying it. I think it's very good when it comes to organ sounds. Probably the best in any arranger. The rest of the sounds are quite good but for example some sounds in the PSR 740, in the same price range, are a little bit better. However my favorite sounds are organs so it suits me very well. It also has a lot of more features than the PSR or any other keyboard in the same price range.
To me the MZ has one major drawback and that is the only reason I have not already bought it. You can't assign Right 1 to Left 2 to RX midi channels. You can only assign RX-midi channels to 16 "external" parts. So I would like to use my "very" old keyboard to play the left parts and the whole MZ keyboard to play the Right parts that doesn't seem to be possible. That's why I considering to buy a used PSR 8000 or more likely a used KN5000 instead. But still the most likely is that I will buy a MZ2000, has just not yet made up my mind for sure.
If you, or anyone else, would know that there is a way to assign Right 1 to Left 2 to RX midi channels after all, please let me know.