I replaced my 14 year old GMC 2500HD 8.1/Allison, which was a fantastic truck (if GM had kept the big block gasser in their lineup I would have bought another one) with a new 2015 Ford F350 SD 6.7 diesel and couldn't be happier with the truck. Powerfull, quiet and clean. Not a single issue or problem. Cheaper fuel and better mileage empty or towing is always nice. Diesel or gas - whatever works for you is the right way to go. Happy trails.