I've got the Gator Evo Tonneau cover. I've had it a couple months now and holding up great. Bought for under $500. I love fact that the cover is flush with the bed rails. Exactly what I wanted.
Here's my 2016 Silverado Z71 LT. So far, I've added 5" iBoard Running boards, Type S Smart Off-Road Lights, Blacked out front & rear Bow-Ties..along with the stearing column & the Bow-Tie on the wheels, I've also added rear lights under the tailgate. My next projects will be adding DL3 mirrors (or tow), adding a 2" leveling kit from Tuff Country, and (I know my wife hopes) lastly putting 22" CK162s on.