So, the biggest pickup i have ever owned was a toyota back in 1986 and a ford ranger some years later after i got out of the Marines, other than that i'm clueless about 1/4, 1/2, 1 ton, which is which...
IMHO you just can't beat the Duramax/Allison. One thing besides that is the GM diesel does not stink like the others, I'm referring to the exhaust. You can put your face near the GM exhaust and not smell diesel.