There would be a reduction in living quarters space, and a reduction in storage. That said, I full timed for 5 years in a Class C.
If you do make the jump, be aware of the ratio of wheel base to length. Ideal is 55%. At 50% a C becomes difficult to drive.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.