We've been in the tandem world for one year and 4300 miles after riding single bikes for 30 plus years. We live in the hilly part of Indiana and have been very pleased with the V-brakes front and rear (Avid Single Digit 7). We also like to descend quickly and don't hold back if the hill is familiar and has good visibility. However, we have ridden singles the last two years on the 3 State 3 Mountain Challenge in Chattanooga, TN which includes Suck Creek Mtn, Sandy Mtn, and Lookout Mtn but we are riding it on the tandem this year. The Lookout Mtn descent has more sharp turns and more traffic and much more braking - enough that we decided we wanted a disc or drum for the tandem.
We have a Santana tandem. We decided to install the mechanical Winzip with the 255 mm rotor (10 inch). We have 65 miles with the brake which has included some braking to keep speed down with our generous supply of sand on the hills and roads which has been spread to deal with our snow and ice of the last month. So far so good but it is going to be a while before I get used to all of the lever travel compared to the way the lever felt with the V-Brake with pads close to the rim. I know I will get used to this increased modulation and I enjoy learning about new equipment but it is a very different feeling from what I am used to. I was wondering though, if anyone has ever put on two power brake boosters to pull more cable - what I think I would really like would be a power brake booster that was designed to pull a little more cable than the current one.
Another thing - after fiddling with the little spade washer / shims to get the caliper parallel to the rotor, I thought it would be nice to see if it would be possible to use the convex / concave washers that the Avid disc brake uses to allow what I understand is an easier alignment. I would have to get a thinner hub adaptor for the rotor to allow for the caliper being moved over but I haven't asked about the different thicknesses available.
If anyone reading has any experience to report with the Winzip Disk or my questions, I'd love to hear them.