The trigger pull on even an M1-A Standard is great, a slow easy pull with a distinct stopping point, and then the smallest additional pressure with almost no more trigger movement and the hammer strikes. You always know exactly the spot when the hammer will hit during trigger pull.
They are super reliable, the design has the next round sitting in the mag pointing pretty much right into the chamber, as close as possible without the tip of the bullet already being in there, not much to go wrong, unlike other guns which rely on perfect timing and precise ammo pressure to load in the next round.
The sights are great too, the Standard model comes with a National Match front blade, which makes shooting at 100 yards plus alot less obscured than a fat A2 style AR sight.
The muzzle brake does louden it up quite a bit, that's the only downside.
And it loads with cheap stripper clips, which is fun, or get a few 10 round mags (most are chopped down 20 round GI mags, but pretty common).
Get one, you won't be dissapointed.