I think gas can move a box truck just fine. Smoother more responsive ride is worth a few extra bucks burnt up. And i like turning an engine on, not turning it slightly to warm glowplugs then turning it on.
Everyone at our base has an opinion. Some are dead set on diesel as "the old reliable" and "way its always been." Some like me like the familiarity of gas.
We have box trucks and vambulances. The box trucks except for one are diesel, the vans 50/50 mix. The diesels are all the aging ford 7.3...