I was a hard core gas man. We've had 2 gas MH's and now a DP. I wasted 75k upgrading. Buy your 3rd RV 1st. Our Discovery DP has a Cummins 8.9L 380 Hp, 1150FtLbs.
We arrive much more relaxed, sooner, more comfortable in luxury. Better MPG, can climb hills now pulling a car (I would not do with our gassers due to lack of torque).
Coffee, microwave and residential refrig look continuosly. I had a hard time convincing wife to buy a DP, but she would not go back now.
I bought new to get the warranties and to avoid buying other people's problems.