How does it do towing the type of load pictured?
Do you run tow / haul mode and let the trans do the work, or manually select a gear?
Does manual mode lock the gear you desire, or is that simply the highest gear it will enter?
How many miles on your truck and have you had any maintenance issues?
Practicality has me leaning toward a newer 5.3 GMC 1500. I have no complaints about my 2005 GMC 1500, so why not?
Of course I would love nothing more than a Cummins, but that is unnecessary at this stage I think.