It is a hell of a lot faster to do cab off. As long as you dont have a chit ton of add on stuff that runs from the cab to the frame. Ive had some that run air bag lines, air horn lines, wiring for air bags and air horns, fuel pump wiring, camera wiring, and all sorts of other chit that it was safer to do cab on so i didnt *** up any add on stuff. Little add on stuff is cab off... Hell i work on our forest service trucks, and the only real pain in the ass is the light bar, which is 4 bolts. They were smart and put connectors in everything. I pull cabs on those to do turbo work, hpfp, etc...