We have stayed at Camping on the Gulf in Destin several times. We always camp in the second row from the Gulf. The first row does not have sewer. Water and electric only. They will pump you out as needed ($). The second row has water, electic and sewer.
As already stated they are pricy and you will get sand in the camper. The up side is you are just a few feet from the ocean. Just walk a few feet and dip your toes in the Gulf. Several times I have set in the MH and watched dolphins swim by. Where else can you do that?
Just purchased an Allegro Bus with Residential Refrigerator about 2 months ago. My first Residential Ref. I would not go back to the old style. The Res. Ref. keeps the temperature you want regardless of outdoor temp. Does not have to be level to work properly. Our has lots of room to store you food.
I remember how much improvement a DP was over a gas when I purchased my first DP. The change to a Res. Ref. is about as drastic of a change to the better.
I do agree with others, I would be concerned if it was not a factory install.