I have found them all to be good! My favorite are parked with no witness holes. Ive got Imbel, StG-58, S.A., Issy, FN, Aluminium, and a bunch that i have no idea about. I have payed no more than ~$5-10 each. I believe that because they were all made to Mil-Spec (no aftermarket I know about) they are all good-Enjoy!