Lots of people don't like them. Since a good two stroke is not that much less, and some cost more, than a four stroke. I don't think cost is the reason. I like two stokes on sleek airplanes, like them to go fast so a good two stroke does that very well. I prefer four strokes on scale airplanes that don't need to fly fast but need the pull for a good climb out, they also sound more realistic. I prefer average powered two strokes on sport planes because there is less to worry about and perform as well as a four stroke.