I'm getting a small.
What it is about Campy is probably more what you are used to than anything else. Better - no, not necessarily although that may be the perception. It's not magic. Well, actually, testing so much over the past few months and never being able to test a bike with Campy (factory bikes just don't come to the shop floor with Campy), I do think the shifting is special, almost liquid and I love the ability to sweep either up or down. I really like the thumb shifters on Campy. Personally, I think it's worth the price initially, but it's familiar and that's the draw for me. I probably wouldn't swap out components if you have a quality drivetrain in place.