Nathan H.wrote a review of Shimano XTR Di2 RD-M9050 Rear Derailleur on May 7, 2016
Familiarity: I've put it through the wringer
Really happy with this RD. I have it on a CX bike set up with a 1x and it works really well. I had a DuraAce RD with a RoadLink but the XTR clutch handles the big range much better without any chain issues.