For 1 x drivetrains, I think there is no question that SRAM has Shimano beat for most people. But I am also starting to see more and more 2x drivetrains returning on 2018 bikes. Check out some of Trek’s Top Fuel and Procaliber bikes. I also find the Shimano system easier to work with mechanically. While the XD Driver is a nice concept, in practice, it just isn’t very refined to work on. The first time I installed a SRAM cassette, there was so much friction in the rotating piece in the cassette, I couldn’t tell whether it was threading in or not. I also couldn’t tell whether I was crossing threading. Finally, I just had to blindly go for it hoping that the thing didn’t strip and thankfully it worked out. But I know others who have stripped the threads. I’ve also had to pull the cassette a few times to regrease contact points to eliminate creaking.
I think for 2x drivetrains, I’d go back to Shimano for the cost and ease of maintenance. Also, SRAM brakes are terrible. I have a cheap set of Shimano MT 500s on one bike and SRAM TLs on another. Everytime I switch bikes the differences is more than noticeable.