space clam, at the top of the compettion, the power is more important than sound. I'd rather have an electric than a IC motor when the electric I believe is now better than IC. My plane is lighter than equivalent IC powered planes, but still more powerful. My plane also flies better now it is lighter. This I see is more important than the noise it makes. With the extra packs, I think a pack last 300 flights, so thats about £1.26 a flight, whereas with YS motor's it's more like £3 a flight. But with the lecy packs you can swap them between planes, like I'm going to do with my Smaragd and Cap140.
But for fun, I still like the nice sound of the four strokes, this can't be beaten.