Monohull sailboats for large bareboat charter fleets have long been built by companies such as Bavaria, Beneteau, and Jeanneau, and they have been standardized to the point that after you have chartered one, you'll find that you're familiar with the sailing, mechanical and electrical systems on any of them. In smaller venues, and in much larger crewed yacht charters, you'll find quite a bit of variation, but in the first case, the boats will tend to be simpler. And in the latter, you'll have a professional crew to explain, and maintain, the systems. In any case, improvements in roller-furling headsail systems, and the use of in-mast furling or lazy jacks for mainsails has dramatically simplified sailhandling on virtually all yachts.
Sailing multihulls have rapidly gained popularity in recent years, especially in charter venues such as the Caribbean. They offer wide, stable platforms for crews to enjoy their holidays, and the combination of space and stability makes them attractive to guests who may be uncomfortable in the narrow confines of a monohull, which will heel as it sails into a strong wind.
Multihulls can be built with two hulls (catamarans) or three (trimarans), but the vast majority of charter yachts are of the two-hull variety. These have separated cabins in their two hulls, plus a wide bridgedeck saloon between the hulls, which also often contains the galley. With roller-furling headsails and twin engines, widely separated, one in each hull, they are often easier to maneouvre than monohulls.
Boat over about 47 feet in length are often captained by a professional, as the size of the boats and the loads on the sailing equipment scale up quickly at that point. Space increases quickly with length, as well, and a yacht charter aboard a 50-plus-foot model can be quite luxurious.