My two cents: (1) the price was high, perhaps, but it isn't going to eat anything; (2) a good case could be made that the original SIGMA SW9F was better than subsequent models as the interior was changed after the suit by Glock to make it less like the Glock in its mechanism. Nothing wrong with being more like a Glock.

By the way, the M&P uses the same or similar trigger return spring with the little tampon insert. S&W tells its LE agency customers to change that spring when magazine springs are changed. Not a bad idea, but I have never had one vibrate itself in two. On the other hand, the problem was discovered so early that I thought everyone knew from one of the original articles about the then-new SIGMA not to get that little tampon wet with anything. So, don't put lube, water, solvent or anything else on that spring.

By the way, the appearance of the SIGMA is not the primary reason Glock sued. The suit included alleged patent infringement over, perhaps other things, but at least the "positive guide means," I believe it was called on Glock's patent application. Whatever the correct term, it was part of the Glock that supported the cruciform sear, thereby preventing the sear from dropping out from engagement with the lug on the firing pin as a result of inertia or other forces, should the pistol be dropped on on its bottom, i.e. the trigger guard area.

The Glock is advertised with 3 safety devices: (1) trigger safety (prevents inertia discharge if pistol dropped on its REAR end); (2) firing pin safety (prevents inertia discharge if the pistol is dropped on its FRONT end or muzzle; and, (3) drop safety, which prevents the cruciform sear from "dropping out" of engagement with the lug on the firing pin. The "positive guide means" is not a part, as in replacement part, but a feature molded into the frame which supports the lateral arm of the cruciform sear to prevent the sear from dropping out of engagement with the lug on the firing pin.

I prefer my SIGMA to have a part such as this, as opposed to it not having such a part.

Personally, I think you should keep it and enjoy it.