We found it important to figure out exactly how one plans to use the motorhome.
I drive diesels, love them, however they're heavy and expensive.
I pack, maintain etc so I want it in the backyard, a diesel would wipe out the under ground sprinkler heads and leave ruts in the yard, not so with our 32' gasser. Also the modern diesel gets the same and often less mpg's than a V10, granted you can go bigger and heavier, but in our case we use it week ends only to state parks within 6 hrs of our home. At 70mph we manage 8mph. My school bus with a noisy Maxx Force gets 3.5 mpg at worst to 5.5 at best, coaches with tags are about 7 mpg with the big delightful Cummins. Diesels with air ride will have a smoother ride, but your paying for it, if you drive much its worth it.
The Ford chassis does need after market parts for better handling, we spent $3000 for Blue OX steering and stabilizing and are amazed with the improvement.
As for interior noise its a given with constant vibration and flexing from road conditions. Tighten what you can, remove everything from the microwave, put paper plates or coffee filters between things that rattle like pots, pans, and know full fuel and water does make for a bit smother quieter ride. If that fails you can always turn up the tunes. With our V10 noise is a constant, but you get used to it.
The key is to figure out what your willing to put up with and what your willing to pay to avoid in a depreciating asset.
Personally if I had a money tree I'd have a big Tiffin rear diesel, and I'd learn to deal with the fact that I wasn't using that glorious coach to its full potential. But thats me. Good luck with the search!!