Different types of boats exist for chartering, depending on whatever type of maritime holiday you have in mind. Your main choices are between monohulls or catamarans. Monohull boats have only one hull while catamarans have two and therefore tend to be bigger.
A catamaran might be your choice if you plan on an extended holiday for your entire family or friends. Both the surface area and the build of a catamaran make the boat very stable and balanced, which creates a pleasant environment for cooking, sleeping, or entertaining, especially if you or members of your party tend to become seasick. More deck space allows for some great parties or sunbathing, and a larger boat overall allows for more separate cabins and more privacy between passengers. Catamarans also average 20% faster speed than monohulls. Most importantly, the buoyancy and multiple hulls of the catamaran make it nearly unsinkable and therefore more resistant to floating debris or treacherous reefs.
As for the disadvantages to a catamaran, its size can be clumsy to maneuver in high winds and because these boats are light and buoyant, they flip easier than monohulls do in a tough storm. (However, even if they do flip, catamarans still float better.) Keeping your boat at a dock might cost more because of the space it takes up, so your trip might be limited by where you can anchor or moor.
Most experienced sailors prefer monohulls, either for sailing efficiency or plain aesthetics. Tacking (steering the boat through the wind so the wind blows on another side of the vessel) becomes much easier because of the monohull's smaller size and larger weight. Some sailors deem the catamaran unbearable because of the tacking difficulty. The heavier monohull sustains more weight than a catamaran, so you can stock up on provisions or equipment. As a disadvantage, monohulls heel (lean to one side under wind pressure or waves) more easily. If the hull damages, a monohull will most likely sink, whereas a catamaran can be almost unsinkable.
Overall, catamarans cost more than monohulls because of the price of charter as well as fuel and the price of mooring. However, prices for both choices go up depending on size and the number of cabins.