When it comes to engines, the money is spent for nickel. The higher the nickel content, the better the engine. They are all pretty much CNC machined nowadays and all have great tolerances. The price difference is for the nickel. OS Max might cost more, but offer years and years of reliable power and they have great customer support. My OS Max engines all start easily, run strong, and require the slightest adjustment only when the seasons change. I wouldn't even consider running anything else.