I was away from the Cummins world for a while I was driving a 01 GM/Allison/Durapad and a 02 GM/Allison/Durapad work truck but I am back with my own 03 SLT 6-Speed HO.
Here is a some what of a objective comparison.
GM definitely has something going with the addition of the Allison transmission. Our 94 Dodge/Cummins and my father in laws 01 Dodge/Cummins automatics could not harness the cummins on the ground. I'd like to drive a GM 5 speed with the Duramax to make a better comparison
GM 245-16" tires come on. 265-17" OOO YYEEAAHH
GM suspension is a nice ride but throw a 2100 lbs hydraulic jack hammer in the bed and there is more sway in the steering/rear end than the hips on the prom dance floor. Can you say bumper squat??
GM is quick out of the hole but add 10,000lbs behind it and your screaming at 2400-3000rpm to do the same as the cummins between 1400-2000.
GM 15. 5-17. 5 mpg Best in warm conditions 13-15 with cut winterized fuel. My 03 running cut fuel is maintaining 19-20. 5 [Under 1000 miles total] (I calculate what goes in the tank to the miles traveled. I get the last drop in also. )
GM quad cab is limited to 26 gallon tank--Dodge almost 10 more gallons
Conclusion. . Hummin Cummins all the wayOo.
Here is a some what of a objective comparison.
GM definitely has something going with the addition of the Allison transmission. Our 94 Dodge/Cummins and my father in laws 01 Dodge/Cummins automatics could not harness the cummins on the ground. I'd like to drive a GM 5 speed with the Duramax to make a better comparison
GM 245-16" tires come on. 265-17" OOO YYEEAAHH

GM suspension is a nice ride but throw a 2100 lbs hydraulic jack hammer in the bed and there is more sway in the steering/rear end than the hips on the prom dance floor. Can you say bumper squat??
GM is quick out of the hole but add 10,000lbs behind it and your screaming at 2400-3000rpm to do the same as the cummins between 1400-2000.
GM 15. 5-17. 5 mpg Best in warm conditions 13-15 with cut winterized fuel. My 03 running cut fuel is maintaining 19-20. 5 [Under 1000 miles total] (I calculate what goes in the tank to the miles traveled. I get the last drop in also. )
GM quad cab is limited to 26 gallon tank--Dodge almost 10 more gallons
Conclusion. . Hummin Cummins all the wayOo.