Its signature longer, more exotic cruises attract an affluent 55-plus crowd, though shorter sailings can skew slightly younger. North American passengers are in the majority, but Crystal takes pains to cater to an international mix of passengers, including a strong Asian contingent -- the ships will provide kimonos as well as bathrobes in accommodations.

You'll also find families on Crystal ships, especially in the summer, as the line has dedicated facilities and comprehensive programming for cruisers ages 3 to 17.

Yes. Clothing onboard Crystal's ships is dressy, particularly on formal nights. Even on other nights, passengers tend to wear cocktail attire (women) and suits (men). During the day, elegant casual is the rule, and you won't see swimsuits, swimsuit cover-ups/robes, baseball hats or denim cutoff shorts in the dining venues. After 6 p.m. shorts and baseball caps are not permitted anywhere for men or women.

On Black Tie Optional nights, held on cruises longer than seven days, men generally wear a dark suit with tie or a tuxedo; for women, it means a formal cocktail dress, evening gown or dressy evening separates. On the evening of the company's themed party, Crystal White Extravaganza, suggested dress is -- you guessed it -- white.

Almost everything is included in the base for a Crystal cruise, including gratuities, unlimited internet, sodas, fine wines, champagnes, premium spirits and specialty coffees, as well as room service. Specialty dining, including Umi Uma by chef Nobu Matsuhisa, is free for one reservation per passenger (must be booked pre-cruise); repeat reservations carry a $30 per person fee unless you are sailing in Penthouse category accommodations.

There are complimentary Crystal Adventures shore excursions on the yacht expedition sailings, but you'll have to pay extra for all other excursions, spa and beauty treatments, laundry and dry cleaning.

Among the most popular activities onboard a Crystal ship are those that involve education of some sort, whether it be how to design a webpage, learning about food and wine, or listening to a guest lecturer talk about history, music or film. At the same time, Crystal's passengers faithfully flock to cruise traditions, such elegant afternoon tea, paddle tennis sessions, nights in the casino and activities like bingo and napkin folding.

Its inventive and diverse shore excursions tend to empty the ships in port. In addition to the more conventional shore excursions, the company pioneered programs providing its affluent passengers with service and donation opportunities to give back to the destinations they visit, and the complimentary You Care, We Care excursions typically fill up very quickly.

Best for: Luxury-loving couples seeking a variety of enriching sea day activities, varied gourmet dining and lounge-style entertainment

Not for: Luxe cruisers expecting huge entry-level cabins, rowdy partiers