The DX7ii I have is a fucking tank of a machine and I'm playing it until it breaks, fixing it, and then playing it some more. I guess I kind of understand typical "car guys" now.

The best part is being able to map the sliders to /almost/ any parameter within a patch, so it's possible to have expressive control over the tonality of your instrument while playing live. Sure it involves menu diving to figure out ahead of time, but I'm a programmer. It's really more about the joy of being like "this sound needs more wonk, lets tie this parameter to the output of this other function and ooOOOH not what I was expecting but let's go"