My Santana Tandem came with Cantis stock and when adjusted well, they were "adequate" I switched to the Avid Single Digit 7s and can literally pick up the back wheel if I want to with the MTB tires on. I haven't tried it on the pavement with the Road tires but the performance difference is at least a factor of five! I was just looking for a performance gain as my wife and I are both larger riders (for now) and the terrain we like to ride includes some hills. I would go disk if the frame provided that option but it does not. The SD 7s with Koolstop Salmon pads is the closest to disk performance you can get in a V Brake IMHO. YMMV.