I have played with them on my profile 3D planes. On my Mojo 40 with a 55AX, flaperons will shorten my takeoff roll from 15 feet to 10 feet. They also tighten up my loops to about the plane's wingspan.

The most useful thing about the flaperon mix, though, is the ability to trim the ailerons up or down in unison (on the ground) without making mechanical adjustments. I think that this is probably the best use of them on a sport plane.

Good luck