I think I am just Filter junkie though, cos I also have a Filter Twin, DOD FX25, Subdecay Proteus, Boss FT-2 (really great filter actually, surprised me!!) as well as the Prometheus and Mutron. Lol!
I've had the Mutron for years and I've never gigged it. I think you hit the nail on the head, it's very sensitive to different basses, the bypass is terrible, and its huge, so it's really best kept for studio use really. The Aggie Filter Twin is currently on my 2nd board so if I do need a filter...That's the one thats coming to the gig!