Originally Posted by AquaHull
The question is, is a 3 pin better than a 2 pin model? I know it won't have the BTF issue, but it is pricey.
Only you can make that call. Personally, if I was buying an older used Glock with the intention of shooting it regularly, I'd try to buy the latest/newest model that I was reasonably certain would work well, if for no other reason than parts availability. Generally, the older the model of ANY firearm, the more difficult it is to get parts for it. In the Glock world, examples of hard-to-find parts might include the old flat-sided (non-LCI) extractors, older locking blocks, and the very early "pencil"/skinny 9mm barrels.
I have several older 9mm models, but I try to do most of my shooting with newer Glocks. Several of my Gen3 guns have the flat-sided/non-LCI extractor, but I bought a few spares several years ago, so if I need some to replace worn or broken parts, I already have them. For folks who don't stock spare parts, the only other option is to send it to the factory and hope they still have a stash of older parts that includes whatever you need.