Without question, Crystal Serenity has the BEST casino on any of the ships I've been on. (Unfortunately, their rooms are the most expensive.) The casino is pretty much the same as any land based Vegas casino as far as rules go. Standard payouts, hand shuffled, 6 deck shoes with typical splitting/doubling rules. Split as many times as you want, even aces. Double after split & surrender allowed.
Princess had the worst. Automatic shufflers with dealers putting cards back in (8 decks) after dealing one or two hands. Not worth playing. Princess is our last cruise line of choice due to this. We like to play when there is nothing else of interest to us to do on the ship.
Royal Caribbean had a single deck shoe in '08 but blackjack payouts were NOT 3-2. Did fairly well on that in spite of no advantage in increasing bets based on cards played. Totally luck factor.
I can't remember Holland America or NCL's casino rules.