In Cuba, you have the chance to stay in hotels or in casas particulares (private houses). But if you want to get to know the true and authentic Cuba, if you want to interact with the Cuban culture and to learn about the daily life of Cubans, then my personal advice is to stay in private homes (casas particulars) in which you will receive a personalized quality service. They are cheaper than a hotel room and they are comfortable and with good conditions, equipped with everything you need to rest after a journey full of activities. In addition the family where you stay can inform you much better about what to do in the area where you stay.
The standard electrical current in Cuba is 110v/60Hz. But the majority of the private rental houses (casas particulares) and hotel facilities are equipped with the 220v/60Hz. Most of plugs are plain, but you can find places that can have the rounded plug. My personal advice if you want to avoid problems is: take a flat pin adapter for the electrical equipment that have rounded connectors. Although in Cuba you can find this adapter, my recommendation is to take it with you already and avoid any surprises.