Another valuable difference to us is the view both driving and sitting parked. In the average DP you have twice the front window space that you have in the class C.
If driving you get a lot better view, especially in the mountains. If you're parked with a view such as over a lake or a valley, a DP's front windows are like the picture windows in your front room at home. While we'll usually watch sunsets from outside, I like to be sitting in the front seats looking out the "picture windows" for sunrise.
If you're in the middle of a DP, because the windows go all the way to the ceiling, you still get a good view. Is you're standing in the middle of a class C, usually all you get is a good view of is the overhead bed.
Bill