When you're looking to take a cruise, there are a number of things you likely take into account: the style of the cruise line (family friendly? luxury? expedition?), the itinerary, the price. But a major factor comes down to the ship itself. You really only want to go on a ship that rates three, four or five stars, and nothing below that.

So what ingredients go into a top-rated vessel? 

Well, five stars are usually awarded by cruise writers to ships for excellence in everything from accommodations to food and service. It's a somewhat subjective rating system, given that every cruise is different, even on the same ship. Crews and chefs change or have a bad day or two. Weather and itineraries play big influences, too. But over time, reputations become formed and repeat cruisers gravitate to one or more favorite cruise lines and perhaps a favorite ship or two. My three-and-a-half star experience could be your five-star dream cruise.

That said, Cruiseable's readers might like to know how I come to evaluate and rate cruise lines and ships after having taken well more than 300 cruises over the years. You'll notice that every cruise ship on Cruiseable has an overall rating assigned — use the Bliss Filters at the top right to compare different cruise ships and itineraries. 

Here are some of the factors I take into account in assigning a ship rating.

Courtesy of Crystal CruisesAttentive waiters make sure your glass is always more than half full on the Crystal Symphony.

Service

Service is often a key indicator of what kind of cruise you can expect, because any top-notch cruise itinerary is going to start with a professional and motivated crew. Do crew members consider passengers pleasures and comforts first and try never to say no to a reasonable request?

I've been fortunate to have cruised on all the top luxury lines, and in my experience, the staff of Crystal Cruises, Seabourn, Silversea, Oceania and Regent Seven Seas all rate five stars for the stellar service accorded to passengers. Crew members go above and beyond to accommodate requests.

One time we asked for a press coffee pot on Seabourn and the hotel manager went out in port and bought one for us. Another time on Silversea, we put in a special request for Patron tequila, and the barkeep went into port and got us a special bottle. However, it didn’t work on a recent Silversea Silver Muse voyage where there was no 100 percent agave tequila (anything else gives me a big headache), so we went off and got our own.

On the mainstream cruise lines' ship, we'd generally give Princess a rating of four stars for service. While they do try hard, it’s difficult to please passengers on larger ships. (You can check out Cruiseable's Ship Discovery Tool and notice that while ships like Silver Shadow and Silver Whisper offer one crew member for every 1.3 passengers, larger ships such as Golden Princess and Grand Princess have a ratio of one crew member for every 2.2 passengers.) Carnival generally gets a rating of three stars in this category.

Courtesy of Oceania CruisesYour meal at La Reserve restaurant aboard Oceania Riviera will pair classic French cuisine with carefully selected premium wines.

Cuisine

Cuisine is one of the most important factors in a ship's overall star rating. My five-star culinary selection starts with Oceania and Regent because of the high quality of the food, presentation and creativity. Crystal gets five stars for its alternative dining venus Prego and Silk Road and four for its main dining room. Silversea merits five stars as does Seabourn, which often offers six star cuisine, but we stop at five.

Princess chefs do a four-star job (sometimes five) in alternative dining venues and three in the main dining room. Don’t get me wrong, we have had some tasty meals on Princess but not consistently, and we’ve taken more than 30 cruises with the line going way back when.

Courtesy of Silversea CruisesSilversea's Medallion Suite offers guests a spacious room with a teak veranda, living room and luxurious bathroom area.

Accommodations

Accommodations are also key and hard to beat in the Penthouse decks of Crystal, Silverseas' top suites, Regent Seven Seas and Seabourn. The cabins are spacious, well equipped with free drinks in mini bars on Silversea and Seabourn and on Crystal in Penthouse deck rooms. Also look for creature comforts such as robes, slippers, beautiful bathrooms, walk-in closets top toiletries and many balconies or all balconies, depending on the vessel. So high fives go to each of them.

Princess has some of the best suites and mini-suites, especially ones in the back of the ship with balconies overlooking the wake. Those are high five worthy. In this category, cabin stewards and attendants play a central role. To merit five stars, these crew members need to do a good job tidying up and going the extra yard.

On lines such as Silversea, Regent Seven Seas and Seabourn, they'll clean your eyeglasses and even fix them when broken or fold your nightgown pretty on your bed and decorate the cabin on a special occasion. Usually, the butlers on Crystal (on Penthouse deck only), Silversea and Regent Seven Seas do go out of their way to please and help the line up those stars. Our last butlers on Silver Muse and Silver Whisper were especially solicitous, but they almost always are on Silversea. The same with our Crystal butlers, couldn’t be better.

I haven’t mentioned Cunard and Celebrity yet, but both are solid four-star operations for the most part. A recent transatlantic trip on Cunard's Queen Mary 2 was definitely worth four nods and even five for some exceptional dinners. Same for a cruise to Hawaii aboard a Celebrity ship.

IAN SCHEMPER / Courtesy of Crystal CruisesTake advantage of big, beautiful iMacs featuring 27-inch screens at the Computer University @ Sea on board the Crystal Serenity.

Onboard activities

Another major factor that determines our ratings system is onboard activities. Princess probably gets a five for having the most options from bingo to disco. Crystal has the gamut of games and sports plus one of the best lecture and enrichment programs, including a Computer University at Sea that can’t be beat (I learned a lot going to those classes). So five stars to them in this category. Seabourn and Silversea offer a more laid back cruise with fewer options. Silversea and Crystal both have do have swimming-size pools. Crystal, Princess and Carnival have the best fitness centers and spas. Royal Caribbean, Norwegian and Carnival, of course, are all about the onboard activities so are good choices for travelers looking for nonstop action.

One of the standards of rating anything is value for the fare or you get what you pay for. Which you do on the five-star carriers.

Courtesy of Royal Caribbean InternationalCatch some high-wire performances in the Aqua Theater during your Royal Caribbean sailing.

Entertainment

I could go on and on. Entertainment, for example, sets some cruise lines above their peers, such as Royal Caribbean and MSC Cruises, which have breathtaking theatrical performances, some of them outside on deck. Even some of the smaller cruise lines, such as Viking Ocean Cruises, are getting into the act with some nice stage shows. Again, use the Bliss Filters at the right to zero in on the factors that are most important to you. 

This report is purely subjective and based on my own experiences. How about yours? Leave a comment below.