I've been running buckets for almost 20 years. I've had both diesels and gas (both GM and Fords) but the type of equipment you want to run needs to be in line with what type of work you will be doing. If you're going to be doing splicing or maintenance work then I always run with the 6.8 V10's. If they're kept up properly, these motors are damn near indestructible. I idle the hell out of mine and never had any issues. Of course there were normal things that needed replaced like hoses, batteries etc. etc. but when you're running a unit day in and day out, do you honestly think you'll be changing stuff at the manual intervals??
If you're going to be doing a lot of towing (like UG work, towing a directional, ditch witch etc.), towing fiber trailers, or a lot of LONG DISTANCE running (couple hundred miles a day or something like that) then I run a diesel. I run a 6.6 duramax on a GMC topkick but your 6.7's and 6.0's or whatever, these were built for something like this. Yes, it's true, any late model diesel isn't designed for extended idling (your dpf system requires more frequent maintenance) but all of these diesels were great at long distance travelling and towing. Diesels like to be on highways, this is why you get so many miles out of them. The gas mileage is better in this instance, more power and towing capacity. On a gas 6.8L for example, it can tow but you're really only averaging 5-8mpg.
