I have about 5000 rounds through a PT609 Pro (an older design very similar to the PT 111). It's been 100% reliable with no hint of trouble. It's not the most accurate pistol I own, but it is equal in reliability with the best of them, and better than some. The accuracy issue could be me, I suppose. I've shot just about every brand of FMJ through it along with Speer Gold Dots, Winchester Silvertips, and Remington UMC (cheap) JHP. It likes them all - even reloads and a few rounds of who knows what that my kid has picked up off the ground at the range. Roughly the size of a Shield but thicker, it is by my side as I type loaded with 13+1 of Speer 124gr Gold Dots.
The only "problem" it has is that the finish is not very durable, and it shows a good deal of holster wear.