I've shot all the above rifles and IMHO, the M1A is the best. It just feels right to me and the irons are superb.
While I don't have any personal experience with the PTR rifles, I have owned an H&K 91, and currentlly have an FAL and an M1A.
If you are a reloader, forget the HK/PTR unless you want to lose a lot of brass. IT isn't the fluted chamber (although that probably does shorten case life a bit -the grooves left from the flutes kind of iron out with resizing) what kills your brass is getting wanged off the back edge of the ejection port, leaving a deep crease, and I felt seriously affecting the integrity of the case.
I got the "ejection port buffer" for my HK91, a hard rubber block riveted to a steel spring clip to snap over the reciever. IT changed the dangerously deep crease to a less deep dent.
Also, the HK safety lever is correctly positioned only for orang-utans. IT is too far forward of the pistol grip to be able to be used with the shooting hand, without shifting your grip 3/4 of the way around to reach it. It is, however well positioned for the European (German) concept of using the safety with the "off" hand.
AND, other things I find less then excellent about the design is the lack of any way to shut the action, other than spring pressure. And the two pins removed for takedown are just that, completely removed, and so more easily lost than a captive pin would be.
Trigger pull on my gun was ok, nothing great, and while the diopter sights were easy to use, I was not able to be very precise. Minute of man, easy. Minute of angle? no.
ALso, I found the rifle to be picky about ammo. For the delayed blowback system to work right, the brass has to be at a certain point between "hard" and "soft". European surplus ammo worked well. US surplus ammo, not as well. and US commercial ammo was ...iffy. One thing you can do on the range, if your ammo isn't working well is a shot of oil in the mag. Usually that helps, but oiled ammo should be shot, not stored.
And last, the HK weighs the same as my M1A, but is about 6 inches shorter. Recoil is mild, but its a lot to pack around.
The FAL is a good rifle, a tad heavy, some versions are rather long. Sights are "good enough", but not great on most versions. Trigger on mine is again, fair. The models with the slim forearm get rather hot to hold quite fast, one magazine rapidly fired (not as fast as possible, but aimed, spaced shots) and the forearm is quite warm. A second mag makes it difficult to hold.
Also one has to be sure if one has an "inch pattern" or "metric" FAL, and use the proper magazine. I'm told the "wrong" one won't work.
My personal favorite is the M1A. Part of that stems from the fact that I was the last group the Army trained on the M14 as a Small Arms Repairman. Another part is that the rifle fits me best, and I shoot it well. Trigger on mine is excellent, after the standard take up. Sights on mine are actually the old Garand T-bar rear sight, and like the rest of the rifle, is capable of more than I am, these days.
The M1A isn't new, it isn't chic, I for one cannot stand the exotic stocks that are so much in vogue these days. IT is an honest rifle, not the best thing for CQB (and never meant to be). Reloader friendly (as much as any auto loader is), accurate as most shooters, and better than some. I don't compete in matches, my old rack grade M1A shoots as well, or better than I do these days, and I never felt the need for a "Match" version, especially at the cost now days.
I wouldn't buy an M1A today, they cost too much, and I already have one.
I've had my M1A for a while, and its not going anywhere. To give you an idea, I paid $500 for the rifle, with a spare stock, scope mount, and scope.
The M1A doesn't scope well with a standard stock, although a good mount is availabe, its not cheap. OF course, nothing is cheap these days. HK makes a mount for the 91, but again, not even remotely cheap. And you can scope the FAL, but I've never done so. The standard stocks are all two low to allow a good cheek weld, so using a scope is more difficult, and a different stock, or some kind of cheekpiece is best, which also adds to the expense.
A couple other "nice" things about the M1A, if needed, you can ensure the bolt closes, and has a generous handle to open it, as well. And, if you really think you need to, you can recock the gun without opening the action.
Now that I'm within visible range of retirement age, the open sights are not as friendly to me as they were a couple decades ago, but I still manage passably well, without a scope. And yes, I am biased for the M1A.