Celebrity cabins are generously sized, with choices ranging from budget-friendly inside cabins to elaborate suites with butler service and dining in a suites-only restaurant. Everyone gets such perks as bathrobes and custom bedding. AquaClass cabins and suites come with special spa privileges and dining in the health-focused Blu restaurant, where you’ll find a muesli trolley in the morning.

Royal Caribbean isn't quite as generous with space, but the line provides a lot of creative cabin choices, from an interior with a virtual balcony to a fancy two-bedroom Loft Suite that comes with access to a private, suites-only restaurant. You can also find cabins that face the interior of the ship at a real value, as well as suites that look out over the AquaTheater, where divers plunge into pools several stories down.

Celebrity Cruises likes to brag that its chefs are James Beard level. That's a stretch, but the food is often a notch above the mainstream cruise norm. Contemporary dining room menus highlight special "Top Chef" selections, but it’s the buffets that really stand out, showcasing both expected and unexpected options. The complimentary choices at the spa cafes include healthy breakfast and lunch choices, while the for-a-fee specialty venues tend to be hit-or-miss.

Royal Caribbean serves rather forgettable dishes in its main dining rooms. Here, too, the buffets are often a better bet. In terms of other eats, there are a lot of really wonderful ways to upgrade your meals, from the proper gastropubs and Jamie’s Italian trattorias on newer ships to the molecular gastronomy Wonderland and farm-to-table 150 Central Park restaurant.

Activities on Celebrity Cruises have a sophisticated slant. You can take a class, for example, on choosing the right wine glass, and a tie-in with Bravo TV's "Top Chef" brings culinary-focused events. We love the Lawn Club on Celebrity's Solstice-class ships, a half acre of real grass on top of the ship for walking barefoot or catching a jazz concert. And the Celebrity ships have Canyon Ranch SpaClub facilities that are some of the best at sea. The line also has a kids program but not much else for the younger age set, so if your little ones are used to being entertained, they may get bored. (As one 4-year-old told us, “This is not Mickey’s boat.”) At night, there's live music everywhere for pre- and post-dinner dancing, and the stage shows include slightly naughty, adult-focused productions.

It's nearly impossible for anyone of any age to get bored on Royal Caribbean ships. Depending on the ship, you can ice-skate, try zip lining, go rock-climbing, learn to surf, or hop in a bumper car. The newer and larger the ship, the more activities you'll find — and the more people trying to do those activities. The ships have excellent kids, tween and teen programs: "Shrek" and other DreamWorks characters make appearances on select ships, and some ships have nurseries. Nightlife is as active as you'd expect: The newer ships have DJ-fueled roller-skating parties, lounges with robot bartenders, show spaces designed for cover bands, and full-length productions of Broadway shows, such as "Cats" and “Grease.”

For us, the choice here is simple: While both lines attempt to serve all cruisers, they both serve their core audiences best. If we’re traveling with kids and looking for energy and options, we pick Royal Caribbean every time, and if we’re looking for a quiet cruise for two, Celebrity is always the clear winner.