I was talkiing to my pet mechanic a few months ago, basically he said there is nothing really to choose between them, as
@theboxers said "They just work"
SRAM Red eTap, he said, makes a neater solution as there are no wires, ASX of course has 12 speed, Di2 has the synchro shifting feature, which may be important to you, Campag has the "Bling Factor", it just looks and feels beautiful, superb engineering too. So what features would you like, and how much do you want to pay? My familiarity is with Shimano, and has been for 30 years, so changing to another brand makes little sense to me, 12 speed makes no difference to me either. ... I just plain can't afford Campag

plus it's Italian and I don't need 11 reverse gears