Just hit 23'000 kms on my 2015 GMC Sierra with a 7.5" Rough Country lift, 36" Goodyear Duratrac tires, Flowmaster exhaust.. all of this has been on or in the truck since 12 kms on the dial..
No issues to date. Drives still great, tows great, and makes offroad in so easy it's almost not fun.
I have talked to many people with a Pro Comp lift on the newer Sierra and Silverado and they have had issues with Axle boots, and differential problems. I installed a 7.5" Rough Country lift on my 2015 GMC prior to leaving the dealership with the truck and have not experienced a single issue. This lift drives like a dream to, I have had many lifted trucks by far this is the best lift I have had installed.