I had a PT111. It was reliable...after I messed with it a little. I never had problems with accuracy.
The three mods/adjustments I performed that made the weapon easier to shoot and more reliable, were as follows.
First, I smoothed up the tang that pulled the striker back. Made a world of difference on the trigger pull. If I ever could have figured out HOW to get the slide apart, I probably would have gotten an extra spring for the striker and nipped off a coil or two and retested the function.
The second thing I did was based on a reliability issue. The slide would fail to go completely into battery fairly frequently when I initially got the gun. I FINALLY figured out that the magazines, even the factory one but moreso on after market mags, were sticking too far up in the well. So I filed down the feed lips, again alot more on the aftermarkets (Promag), until the slide did not hang up any more.
The last operations were not critical to function but they made me feel better. I poliched the breechface and barrel ramp, and slightly beveled the loaded chamber indicator (coupled to the extractor) so that rounds would feed better.
After all these were done the weapon was as close to 100% as it could be.
I read on another site that the original design for that series of guns was in a 9mm format. As a result the .40 and .45 models were more problematic. Not sure if this was true.
I actually liked the thumb safety. I operated the PT111 exactly like my 1911, and USP40. So the concern about confusion in a crisis did not come into play.
Finally, I sold the weapon to a relative who wanted more than a NA Firearms .22mag revolver, but did not want a "big gun." I have pretty much retired from 9mm anyway. I did not sell it due to any dissatisfaction or performance issue.