A lot depends on what type of plane your going to use 20* flaperons on. A big floaty Ultra stick maybe, but try it on a World Models 40 size P-51 Mustang, throw in a little cross wind for good measure and sooner or later it will snap on you so fast it'll barely register in your mind what just happen to your plane.

The problem I refer to is at low speed landing, not tooling around in the sky at speed.