QPAS is great. It has a very unique character that may or may not be what you are looking for. If you are looking for a more "vintage" sounding filter or something with self-oscillating resonance, QPAS might be a good second filter. Be sure to watch some demo videos (MylarMelodies and DivKid have good demos for QPAS). I would recommend taking a look at the Future Sound Systems Timbral Sculptor too. That thing never fails to impress me.
You didn't mention what kind of music you are hoping to make with modular. Maybe give us some details so that we can steer you in the right direction.
Have fun and good luck!-- farkas
In terms of music - I mostly do variations of ambient, but would want to do something more hard (industrial)
Deus, Dei, Daemon