I am probably posting this way too late, but maybe other will find this info useful:
This is what my wife and myself think of Costa:
Ships: Mostly spanking brand-new ships, they do have a couple of "older" ones that they use in other parts of the world but those too are kept in immaculate condition.
If you are going on a Caribbean cruise, you can expect to be on fantastic cruise ship similar in style and layout to Carnival's Spirit-class ships.
Crew: How bad can it be if the crew gives the ship the ambiance of being in Italy? In my book, that's a BIG plus +++++ As for the language barrier, the negative comments that you hear about crew that don't speak English are just BS from some disgruntled cruisers. In all my 50 cruises including the many with Costa on most of their ships, language has never been an issue for us. My wife speaks 3 languages, I speak 4 but on ships I do not recall ever communicating with the crew in anything other than English. Of course, they don't speak it with an American slang! The only times we have spoken in other languages other than English is when you meet passengers onboard of other nationalities and it's a great feeling to be able to communicate with them using their language....OK, OK, OK, I know I'm bragging. As far as Pursers Desk staff/employees are concerned, give me Costa's anytime over Carnival's or NCL's amatuers.
Food: The Mrs and myself both agree that we think that Costa must offer one of the better grub offerings to be found anywhere on the high seas.
How much better can it get when you are presented with at least 3 different Theme choices even at the many buffet stations catering to anything from Italian, French, Indian, Greek, Chinese and Japanese food. And yes, the almighty Hamburger, Cheese and Fries too, plus ball-game size Hot Dogs. Not to mention the "regular" and traditional food selection of Lobster, steaks, escargots etc.....Believe me, if you like to experiment with food, Costa will be bliss for you. If you don't like to experiment and you are happy eating "American fare" and salads, you'll be kept plenty happy too.
Shows: Let me make sure you hear me by yelling this out LOUD "I THINK THAT COSTA HAS THE BEST DARN SHOWS TO BE FOUND ON ANY CRUISESHIP, PERIOD! IF YOU LIKE THOSE WONDERFUL ITALIAN CARINVAL(E) COSTUMES, YOU KNOW THE KIND THEY WEAR DURING THAT FAMOUS CARNIVAL OF VENICE, YOU WILL BE AMAZED BY THE COLORS AND THE QUALITY OF THE OUTFITS. (sorry for the yelling) If your fancy is for Las Vegas style revues and showgirls with their bare asses showing, you'll get your fill of that too.
Casino: As any other cruiseline, Costa will be just as happy to take your bets and your money. One-armed bandits aplenty as well as table games. I wouldn't bet on having better odds of winning on Costa But if your aim is to lose a bundle each and every night, you'll have plenty of opportunities at that.
Smoking is allowed in the Casino and whatever restrtictions apply to other cruiselines, they apply on Costa too. You can smoke to your hearts delight in your cabin (like on the majority of other cruiselines) but you sure as hell cannot nor will you see anyone smoking in any of the restaurants nor in the main theater. Some bars and lounges allow smoking, but then again that is the norm on other cruiselines as well.
Some final comments: I hate to say this being a US citizen myself but your average European is way more educated and civilized than your average American. Anyone stereotyping Europeans as being rude and pushy needs to take a very long look in the mirror. You'll find most of them are people whose world ends at the end of their hometown Main Street, Anytown, USA.
Annoucements made on the PA system are usually multi-lingual: English, Italian, German, French depending on the passnger load on the ship. Nothing wrong with that. ONE BIG BONUS: YOU WILL NOT BE BEATEN TO DEATH WITH ANNOUNCEMENTS FOR BINGO, THIS SALE, THAT SALE, THIS TOURNAMENT, THAT TOURNAMENT, IN SHORT, YOU WILL NOT HEAR 24/7 ANNOUCEMENTS TRYING TO NICKEL AND DIME YOU FOR THIS AND THAT! I don't have any problem with that!
I will go with Costa anytime, in a heartbeat. Oh by the way, historically we have always booked inside cabins and I kid you not when I say that with Costa we have been upgraded something like 70% of the time. A couple of times from the cheapest inside to one of the best balcony cabins on Tiziano deck! Although as you know, there is absolutely no guarantees on that one.
I will get off this soapbox now and I hope I have convinced you to give Costa a try. You will be very plesantly surprised.