We bought the daVinci with zero tandem experience after test riding Santana, Co-Mo and daVinci. There was not much difference in price for similarly equipped rides. Since we were just getting back into cycling and being both "seniors" the wide gearing was attractive; we're in NorCal and flat riding would be extremely limiting. Also, I'm a bit of a geek and the unusual nature of the dV was interesting. So, the ICS was not the deciding factor, but we do like it very much. Starting on what for us is a steep hill (10+ %) is much easier with ICS, but I don't dawdle in getting on the pedals; as seniors we do sometimes have to stop on longer climbs.

Getting in sync is so automatic that when I try to experiment with OOP my wife can't consistently get there she is so programmed to be in sync. I can spin my wife out, but with a 60-11 top gear I just keep things under 95 rpm and all is good. I'm not good much over 100 anyway.

I do prefer the Campy shifters to my Shimano single-bike setup, but I didn't know that when I bought the dV. The front shifting is not indexed, but I'd rather have the four chainrings than indexed shifting. In my next life I might consider bar ends with a friction front shifter and indexed rear. Since we're not a strong team I won't hesitate to go 10-spd once dV has the modified RD available.