I don't mean to rehash an old thread, but I'm new here.
My $.02--I use the Rect-O-Verb Series II effects loop with a rack mount FX unit (Rocktron). It sounds great; it includes an EQ section, flange, chorus, delay, phaser, roto-speaker sim, and pitch change. Other than being finicky about how much level the Rocktron will accept iwth chorus settings, I'm very pleased.
The Rocktron works with a matching Midi pedal, which is not so great. The Expression pedal response is s-l-o-w. It's good for volume, intensity and rate changes, but for real-time pitch changes, yuck.
I'll experiment more as funds allow!