Service

What style of service do you like?

Service on cruise ships will almost always be substantially better than service in a comparable land-based vacation (thanks to low turnover, rigorous training and oversight, and the ability to recruit the best staff from around the world).

That said, different cruise lines have different styles of service. For many experienced cruisers, service style is an important factor in how they select a cruise. To get a rich sense for each line's style, we recommend reading the Savvy Guide to each cruise line, and perhaps a few Cruise Journals.
In the meantime, we offer this overview:

Friendly, informal

Carnival has a friendly, happy, and relatively informal style. Waiters and bartenders frequently strike up a conversation, crack a joke, and share their positive attitude. That said, Carnival officers and crew are always scrupulously proper. (No fraternization, and guests are never touched except to shake hands.) Crewmembers are generally knowledgeable and helpful.

Efficient, professional

Perhaps because both lines have especially large ships, RCI and Princess crewmembers focus on their duties and carry out their jobs in an efficient and professional manner. Crewmembers generally appear happy, but - with the exception of bar staff - do not generally engage in social conversation with guests.

Caring, respectful

Crewmembers on Holland America Line and Windstar Cruises have a warm and caring style. Guests are greeted by name, preferences are remembered, and crewmembers often go out of their way to make sure everything is perfect. While crew are friendly, they are also notably respectful: "Ma'am" or "Mrs. [Surname]" is the normal form of address, not "Hey there."

Efficient (but discontent)

Celebrity and its offshoot line Azamara generally have knowledgeable, efficient crewmembers. However, they are generally not overly cheerful and guests report hearing grumbling and complaints from officers and crew much more often than on other lines. Celebrity and Azamara crewmembers also appear to be less proper: While we have had no reports of serious problems, we have seen officers fraternizing with guests (or attempting to), and crewmembers who touched guests' shoulders, arms and backs.