Well, as for SRAM vs Shimano, it's been so long since I've used Shimano that I don't think I could make a very intelligent comparison, but what I do like about SRAM is the slightly more mechanical feel that I loved about Campy, with the added benefit of being able to find things like chains, cassettes, cables, etc locally. After a few years on Force and Rival, now Red, I've been really pleased with having made the switch.