I started with klotz and switched to amsoil, only because when I pulled one of my banshee motors apart I didn't like what I saw, and then the same with one of my R motors too. It was like there was honey in the cases and the dome and piston was built up with too much carbon. I have pulled my R motors apart after amsoil and they look great, I was sold at that point. Been running it since then and I wont change either, But I miss the smell of my benol.