When I was looking at a TT I gasped at the thought of going from 17 mpg with my PUP to 10 mpg with a TT. We had rented a TT so we knew what the gas milage would be.
We gave a long hard look at Aliners and Trail Manors but just could not fit it into our budget or our travel style.
In the end we found a three year old 25 ft TT for just under $15,000. You can buy a lot of gas for the difference in price.
There are many more intangables between the different styles of RVs; and that usually is what sells people on any given model.