I've got a Shimano 600 single on one of my bikes, and a 105 dual on my other bike, and the dual pivot is definitely 'grabbier', but it's more sensitive to adjustment. On the flip side, it also depends on the lever you're using - I've tried both standard road levers (old 600 SLR levers) and a tektro tt lever, and the tt lever definitely seems to give you more leverage than grabbing the road levers from the hoods, so I run the road levers with the stronger brake, and vice versa to even it all out.