Hi, Ian:
First time I've been made aware of the Ferrofish module.
I see mixed reviews about it online, but if it works for your music, then that's the tool you should have.
I just got a Behringer Model D (Moog Minimoog clone) early in the summer, so my wife would have a few objections to adding another module to the lineup.
She says the three Hammonds in the house already should be enough.
My wife doesn't understand me.
All the best.
David