I have put about 8000 miles on my R3 with 6870 since the beginning of 2015 and 4400 miles on my Roubaix with 6800 since the beginning of 2017. Di2 sure is nice. I am in the planning stages for my next bike and it's either going to have the new Dura Ace Di2 or eTap. I haven't decided yet. I can't warm up to that awful fugly Dura Ace crankset.