Boss VF-1 Effect Processor

I have a GP-100, and may sell that and get a VF-1. I am planning on 
using it for the effects only, as I am also getting a SansAmp PSA-1 
preamp for the main guitar sounds and using the VF-1 in the effects 
loop. Can anyone compare the GP-100 sounds with the VF-1?

thanks
Dave Eichenberger: guitars.loops.devices
http://www.hazardfactor.com/dave