Not sure how many threads there have been on this topic but as a generalization:
DP pros: Ride comfort, noise level is less, power, longevity, better for longer days in the saddle and long trips, usually better equipped, more capacity
DP Cons: Cost, fuel cost, maintenance cost
Gasser pros: Cheaper, cheaper to maintain
Gasser cons: Nice ride but worse than DP, less power and capacity
There are more points but that's the gist. You get what you pay for. If you have the money and want a DP and will use it, by all means that's what you want. If you want to save half your money and still get a nice RV, have less to tow etc, get a gasser.
Above all else, floorplan should drive your choice.