Most food and soda type drinks are included with some exceptions.
Alcohol is not free. They do offer packages and you can bring a limited amount of wine and beer onboard.
Bottled water is not free. There is a tap water option at the soda drink stations and you can get glasses of water free at main dining. You can bring your own bottled water with you. They do sell it onboard but it's crazy overpriced.
Soda is free from the drink stations and at main dining. It is not free if you order from room service because they will bring you a can.
Room service is mostly free but there are certain items I've been told that are extra (i.e., the soda cans).
Specialty coffee is not free. There is regular coffee offered at the soda drink stations but any fancy latte frap thing is extra.
Theater snacks are extra. We always grabbed cookies and ice scream from the free areas on deck and brought them down if we wanted a snack.
Sailing concierge does have some perks with the price tag. They have a happy hour each night with free drinks. You can get endless, free, bottles of Evian in there. And they have one of the fancy coffee machines for free espresso and lattes.
The adult specialty restaurants also have an upcharge to dine in them.
Dining is rotational and your waiters follow you each night. You either eat main seating around 5:30-6:00? (Can't recall) or second seating at 8:15 (we prefer second). I've been on Dream and Fantasy and they have 3 main dining halls, Animators Pallate, Royal Court, and Enchanted Garden. You will hit these at least once in your trip. There are quick eat places that serve hamburgers and pizza and such on deck 11 as well as the Cabana buffet.
I don't drink and my husband drinks lightly. We only ate at the buffet for breakfast and lunch and main dining for dinner. Our food bill was just a few beers he ordered at dinner.
When we sail concierge, our extra food bill is $0 because he gets his drinks from their free happy hour every night.
I've never sailed another line but husband has done Carnival and says their food was just as tasty (he hated the rest of the experience). Oddly enough, the one time we spent the money and ate at Palo we didn't like the food as much as main dining.