I downsized to a class C for the last one. It had the same storage the 32 foot Adventurer had but they did that with a huge back storage area so although it had the same in cubic feet it wasn't as organized.
Class C units use smaller parts so things like wheels/tires, rotors, driveshafts are smaller and easier to handle than the bigger truck chassis if you do the work yourself.
Class C don't always have the carrying capacity and frequently are easier to overload.
A dealer once remarked on how they get more of the C class in for cab over leaks.
The mpg is not that great of an improvement esp if you tow a car.
I am going back to a Class A. I am in the Northeast and drive the GSP in jersey constantly so I have to negotiate the very narrow toll booths there. I found the Class C is harder to line up due to how the box sticks out and most of the tool booths don't have adequate approach markings on these to make it easy to align the RV during entry. It wouldn't be a big issue for most people, but I have to go through them very often so it gets to be a pain. They were made when nothing was wider than 7 feet going through them...
I like the ride height of the A better also.
I will miss the cab over bed. I used that when I needed a nap in the day, with thermal curtains installed I could go up there and black out the brightest light and plus it had the fan up front to keep me comfortable. It was hard to get up and down the factory supplied ladder though, they are not made for grown ups...
Life and circumstances change and I may end up going back to a small C class sometime in the future... all depends on what best suits the purpose at the time.