I use the heavy duty JR arms on almost everything, however, I still use the dubro quik link clevis's too. I don't want the metal to metal contact, I don't use ball links if I can avoid it and honestly, we overpower our flight surfaces so dramatically in most cases the servo arm doesn't NEED to be metal.
I can honestly say I have never had a servo horn fail, or one of the quik link clevis's. I've never had the plastic arm strip from the spline, never had the hole give out or had the arm break. My Kingcat, Raptor, and under Tom's recommendation, Firebird all have the plastic JR arms on them.