Mutts quad clamp is useless. Unless your slit goes that high up, it's completely useless. (and ugly/un-aerodynamic)
The SCS clamps on SLITLESS bars. It's only there to keep your bars straight, not to clamp it onto a fork. You can't compare the two. (Clamping on a solid tube (no slit/perforations) won't make it "clamp down", where as slitted bars.. when you clamp down on them, the slit is pinched together, which makes it clamp onto your fork.)
Clamping above the slit is bad for the bars (yes, it really is) and just plain useless. You're better off with a stock double clamp.
HOWEVER, I don't know much about Blunt bars. So I really can't say anything about them.