The big advantage of a 3 blader is that you can run a smaller diameter prop on a given engine. It will load an engine with a smaller disc area. This helps if the plane has a low ground clearance. It is also a good scale feature on some scale models. Otherwise you are better off with a 2 blader. They are cheaper, usually more robust and a lot more efficient. There is a multitude of choices in 2 blades. Different brands, makes and models There are tons of different materials,shapes ect. It really does not pay to use a 3 blader unless there is a need.

Mark Shuman