I don't get it. Brand rivalries aside, what's the "pecking order" of Ketron arrangers? They're rare and hard to find. If I wanted to try one, I'm not even sure what I would order.

Is the SD60 better than the SD90? Where do the modules fit in, feature-wise? I know the MidJay Pro was more expensive than the SD3 at the end of its run. And it looks like they just released an SD3 version 2!

Which are MOTL and which are TOTL, what are you gaining and giving up? I'm confused.