I've had trouble with the fact that the Cobra fibers stick too far away from the pin and are easily broken off. Toxonics tried to solve that with the Metal Optic Pin but I haven't been able to get my hands on one to evaluate it. The Spot Hogg thru-pin design is pretty durable but they get broken pretty readily as well. I have had decent luck with my Sure-Loc Leathal Weapon but only after investing in a FitzFiber upgrade (much less brittle and way brighter than stock pins) and the lense adapter ring for added pin protection. For pure pin durability I'd lean toward the Spot Hogg with Fitz Fibers (www.fitzfiber.com) and their pin guard.