I’m a Shimano fan
I think as with bike frames, wheels etc, you make some kind of emotional connection with the groupset you decide on, and then try to rationalise it with perceived performance benefits over its competition.
I have ridden both a fair bit, and for me Dura Ace is my favoured option. Campag has all that racing heritage, uses lots of exotic materials and is very pretty. But for me it is clunkier feeling than Dura Ace, and I don’t find the brakes as smooth and light feeling. Dura Ace is a good price for the quality of equipment you get, I think you pay a lot for the materials of Campag, which I don’t think actually add anything to it’s function.
I liked the fact that Shimano held out from using carbon just for the sake of it on things like cranks etc, it’s not lighter in most applications and is much more susceptible to damage. It’s a shame the new Dura Ace uses carbon brake levers, as this is such an easily damaged item, I’ve seen so many chips on Campag brake levers, and that would really annoy me.
Shimano have been responsible for so many of the major leaps in groupset efficiency over the years, ie, indexed shifting, external bb’s (works on road bikes anyway)etc, and I will continue to use it for years to come
11 speed holds no interest to me, 10 speed is more than enough, and to be honest I was more happy with 9, more robust and less need to be so precise in trim.