My personal preference is for regular flaps over flaperons. I have not had good results with flaperons, especially if I have had to do any wing leveling.

Someone told me that using the ailerons while the flaperons were deployed did not allow "adequate" movement of the ailerons AND created uneven drag - ie, producing uneven lift and also creating a "turning" effect on the plane.

I don't know for certain. I did 2 flights with flaperons and was NOT HAPPY with the way the plane performed while landing. They were converted to regular flaps and I was substantially happier with the performance and handling of the plane while landing - the plane was a lot more stable, especially if there was a crosswind.