Russ,

If you want a sound that is close to KETRON's, I would think KORG would be next (Pa3X). With it's editing tools and strength, you can create a lot and still benefit from the Arranger section when needed. Roland would be next in line ...again if you're trying to get close to the KETRON sound without having a KETRON. Also, if you have some 'down' time, you could tweak the Korg to your perfection too.

Just my thoughts ...