Thanks guys, looks like both are good. I actually have a pmdx-122 stashed so it's pretty much even Stevens as to which to choose.

The CSMIO has all 24v digital input/outputs which I think is less affected by noise than 5v. Also it has 2 analogue 0-10v outputs for vfd control so i'm still leaning towards that, but the ESS looks good too! Decisions decisions.

Cheers
greeny