If you hit the casino, Carnival Mardi Gras is the best at sea. Almost all non-smoking including the casino bar, and the smoking side has fantastic ventilation so it doesn't permeate the whole place. On Royal, the smoke is thick and they do not enforce people smoking at the non-smoking machines. Your clothes will reek of smoke for the remainder of the cruise. Drink service is outstanding. Not unusual to be approached by 3 or 4 waiters every 10 minutes. Just got off Royal's Brillance and on the 4 day cruise was approached only once by a waiter.