Mandrel vs crush bend; Worth it?

I build my exhaust systems from pre-made mandrel bends. Crimp bends offend my visual sense of what's right, but I doubt that there's much difference in performance. I build my systems because I usually want a very specific fit that I usually couldn't afford to have a muffler shop build even if they were willing to do it. I only buy 180° bends, usually from Columbia River Mandrel Bending. I also make the systems with stepped flanges so that I can easily take sections of it out as needed. Valiant exhaust pics start a little down from the top here.