Inboard or outboard really depends on the type, use and size of the boat. Then type of inboard be it inboard/outboard or shaft drive makes a huge difference. If your looking for a normal trailer boat (speed/fishing boat) get outboards. Out boards on pods are imo the way to go. A single 300hp gets better performance then twin 150hp but twins give you a back up motor if something goes wrong with one. Every boat is so different in handling and what type of motors suit, its not like a car or truck where you can compare engine types, you can only do this on boats if they are very close to the same boat.