Swings and roundabouts.

All things considered, I'd say Shimano > Campy > SRAM, but there's not much in it and SRAM's coming up fast. The smart (and rich) gearhead picks the best of each, and fettles it all to play nice.

If I had a full Campy group I'd ditch the rear hub for Shimano. A full Shimano group kinda cries out for the STIs to be piffed for Ergos.

I'm pretty interested to get my hands on a pair of Doubletaps...