Longevity is my main concern when talking gas vs. diesel. As we all know, any emissions intact new diesel just has more systems that can fail over the life of the vehicle. Now, if you plan on trading it in every 2 to 3 years then buy the diesel as it does have benefits over the gas truck and you'll keep it under warranty. If you plan on keeping the truck long term, outside of the factory warranty then I would go with a gas option.
I know this is backwards of any traditional gas vs. diesel discussion but that how you have to look at with today govt and laws. Most of us want the diesel but not many will pay to properly delete the truck nor do we want to be harassed when it comes to other warranty issues, registration or being hassled by police or DOT who looks at your truck a little too closely. The gas motor has it's issues too in regard to lifters and the Active Fuel Management (AFM) system but IMO they are easier to address and we all know how much abuse an LS motor will take.
I would personally love to delete my new L5P, not for power, just so the motor would run cleaner and not continuously build up soot. But when I looked into it, no aftermarket shop will touch it and it's a black market deal to get it done anymore at the tune of $10k plus. No thanks.