I have a Cortex in my Eurosport and I throw that plane around very tightly and violently in all 3 axes. I have never felt the Cortex is fighting me, but I had altered the stick priority by quite a lot before its first flight because I learned years ago that a gyro is only of use to me when sticks are at neutral and I see no point in it still having any effect once the stick is moved more than a small amount away from centre. That way the gyro gives me expo around centre but it fades out very rapidly as the stick is moved, and by 1/4 to 1/2 stick travel the gyro is disabled. I suspect that people finding the gyro is fighting them need to change stick priority a lot so that the gyro is quickly disabled.
It is easy to manually check the effect of stick priority. Turn the aileron gain up to max and rock the model from side to side noticing how the ailerons respond to the gyro, now start slowly moving your aileron stick until the ailerons stop responding to the gyro. If they are still responding almost to the end of stick travel, try altering the priority so that they stop responding to the gyro at a lot less stick travel.