All four lines offer a premium experience over and above the mass-market lines, although some may be owned by a MML. First, draw yourself a chart and list the amenities you wouldn't mind paying extra for: "premium" dining venues, alcoholic beverages, shore excursions, airfare, crew gratuities, ship-to-airport transfers, and pre- and post-cruise lodgings. Then list the cruiselines that offer them as part of their "base" price. That'll give you a basis for finding a cruise that's affordable and worth the price. Otherwise, you may end up paying for benefits you'll never use, or can find (and even less expensively) on your own.