the standard bed is 6'9" vs 6'4" on GM vs Ram......its deeper, wider, and longer....plus has better tie down locations......was HUGE for me in buying a new truck.....idk much about diesels but everything ive read or seen says Dmax and 10spd are flawless....the GM does ride really nice for HD truck....and GM reliabilty is typically better (not always but generally)......Ram does have nice interior for sure and truck is more than capable.....i like 12" screen, layout and storage on Ram but other stuff was more important to me plus I just like the look of GM truck better, and 8" screen is more than enough....Ram front end bugs me, lol.......to each their own, either will do