We have a small (24 foot) Class C with no slides, but on the rugged Ford E450 chassis, so:
1) It never overheats in any conditions.
2) We can carry anything we want weight-wise, in addition to having all tanks full with no effect we can feel on how it handles, or stops, or accelerates.
3) Since it's small, it can be heated and cooled fast and efficiently for good drycamping in just about any weather.
4) It's small enough to take into towns shopping and small enough to fit into the older, intimate, and beautiful state/county parks - even into tent sites.
5) It's 29 gallon grey water tank, 39 gallon black water tank, 45 gallon fresh water tank, 18 gallon propane tank, and 55 gallon fuel tank make for many days of drycamping for two people and make for long travel distances between fuel stops.