Have one on my Beretta 682. I love it. Easy to adjust LOP as well as the recoil dampening. Pad adjusts vertically as well as horizontally. It does make the gun more butt stock heavy but I have found the added weight only adds to the recoil reduction. Good reliable system. I am sure the PFS is better but the price for a PFS is more than double and the RAD IIa works as advertised.
I also have a Gracoil on my backup gun a Browning BT99. It works great as well however I prefer the RAD.
RAD IIa on right. Gracoil w/adjustable LOP on left.