ORIGINAL: B.L.E.
Because you only hear an exhaust eplosion every other revolution on a four stroke engine, they sound like they are reving slower than two stroke engines. Actually, their ability to rev is not that different. As you get to the larger sized engines, it is the four strokes that can outrev the two strokes, this due to the two stroke engine's inability to reload the cylinder completely during the extremely short time of the reloading phase at higher rpms.
Yes, this is yet another reason that as you move up, the four strokers gain an advantage.
At the smaller size the OP is talking about however, he is better off saving the money, which really was the original question.