Which is best depends on your needs.
"C's" top out at about 31' and 14,000 pounds. A "c' that big would have a ton or rear overhang and not a lot of carrying capacity. But it would camp real good, have all the extra's, and room to sleep 4-6 or even 8.
"A's" start at about 30' and 18,000 pounds, and go (way)up from there. Most "a's" are built for 2, though there is always a convertible bed or 2. A's typically have goodies like generators, sometimes inverters, leveling jacks, and of course that view out of the huge windshield.