I liked the power of the V-10 motor, which was much more instantaneous than the Cummins diesel. The turbo lag on the diesel takes some getting used to. I give the diesel motor full throttle and it just bogs for a few seconds, whereas the V-10 would be smoking the rear tires if I gave it full throttle all at once. The V-10 motor is a great motor, and very powerful. But then the Cummins diesel is also a great motor, with good power. I can't say that either one is better than the other for towing the load I tow with my truck; they really seem to be equal in actual towing power.
I got the diesel because everyone, and I mean everyone, said the diesel would tow better, which I haven't found to be the case (yet). My diesel isn't broken in yet, so it may get better. But even if it gets better it will only be marginally better, not the leaps and bounds better that I had been lead to believe, and was hoping for.
Unloaded fuel mileage is clearly better with the diesel though. I got 10 mpg empty with the V-10, and I'm getting 14 mpg empty with the diesel. The V-10 would loose 4 mpg when loaded (getting 6 mpg while towing). My diesel looses 6 mpg when loaded with the same load (getting ~8 mpg while towing).
I think one thing that will come into play here, as I keep this diesel truck for the long run, is that it is expensive to get more performance out of the V-10 motor, whereas it is cheap to get more performance out of the diesel. It will cost you ~$1000 for a set of headers and dual exhaust for the V-10, and that is likely the first mod you would want to do being as the stock exhaust is very restrictive. That $1000 will get you roughly 50 more horsepower over stock. If you spend $1000 dollars wisely on the Cummins diesel you can easily gain 200 HP, and that (I think) will be the big difference between these two motors. If you planned on keeping the Cummins diesel totally stock I don't think it is worth the extra expense at truck purchase, and the extra expense at the purchase of each tank of fuel, given that diesel cost more than premium gasoline around here.
Mopar.