what type of servo arm to you all prefer... round , x , or six point and are the avantages or disavantages?

thanks

There is no adavntage of any one type over another, it is all what you need for the specific application.
Examples,
Retracts, round arm for the 180 degree movement.
Wing mounted aileron, long 4 armed with 3 arms cut off or 2 arm with one cut off for extra reach through plate slot(4 arms tend to be longer than 6 arms)
Each size and shape has its own uses.

I use what ever works best.

Gibbs

I like 3d arms, even if I'm using them on a 3d plane. By placing the pushrod in the outside holes on both arm and control horn, you can increase the speed at which the control surface travels from neutral to full deflection.