I'd only buy a model with a dash in the model number. I have an S&W 4516-1. The only issue I had with it is that I bought it new and it had a badly fitted barrel. I sent it back to S&W and they fixed it at no charge. The replaced the barrel and the armorer made sure it was fitted properly.

The 2nd and 3rd generation metallic frame pistols are or were (depending on the service life of the pistol) on the approved list for many law enforcement agencies.