Diki,

I think the Pa600 is a perfect companion for the S910 - IMO they are about as equal feature for feature that you're gonna find in the arranger world. So yes, it's not a perfect comparison, but a fair one.

The S950 may not be as close. The improved guitar distortion effects are very nice, which gives it a slight edge.

BTW I think you meant "incremental" not "excremental" - phew!