More oil content. Also there is just something about the high nitro, maybe you don't tax the engine as hard (more HP, Not using it). But I notice the engine runs cooler. Also throttle response is crisper which helps in hover. All in all I find the motors run a lot better on 30%. I use it in all my 4 strokes. Also, I actually lean the engine down to make them run properly. I get better mileage with 30% so even though it costs more per gallon, it's offset slightly by not useing as much fuel.
Thanks,
Barry