I can comment on the Campy shifter/Shimano drivetrain mixture using a JTEK Shiftmate, as my setup is quite well broken in now. I'm using Campy 10s brifters and a DA cassette, front and rear derrailleur and an FSA crankset. Everything is working EXACTLY as it should--no problems with shifting at all. I rode about 100 miles or so and then needed to do some routine maintenance in terms of cable adjustments, but after that its worked like a charm. Like another poster mentioned, I feel the Campy shifters just fit my hands better than the Shimano ones do. If it wasn't for the Shiftmate, I think I would have spent quite a bit more money than I did to be able to run the Campy shifters. The mixture of Campy and Shimano has worked very well for me though....