I have been riding DI2 since it was first introduced. I tried SRAM EAGLE XX1 on my new Jones mtb, but sold that off in a hurry and replaced with XT Di2. It is so nice to have the perfect-ever-time shifting of Di2. Sure, the SRAM stuff worked like it should, but was clunky, noisy, and crude compared to Shimano Di2. I went with a 2x drivetrain since you can program a single shifter to shift both derailleurs, and this way I had extra range. I know several folks who run Di2 with just a rear derailleur and 1xalso an excellent setup. Shimano Di2 is worth the price of entry.