So, knowing MOA is basically a way to express the cone of dispersion in shots fired, what is good or bad?
Military standards - as far back as the 1950's, and certainly even earlier, is a 2MOA group of ten shots using the milspec rifle and ammo. That means it's a 10" group at 500 yards. And the standard is with ten - 10 - shots, not less. The reason is that probability and statistics math show that a ten shot group is an accurate presentation of what the barrel really does. Less - like three or five shot groups - can leave the shooter with a sample, not the whole picture. Adjust the sights using three shot groups and shooters often end up "chasing the zero." It's because that center point of the group doesn't represent the actual - it's only three random shots worth of information, not a full sample, and certainly not from a fully warmed up barrel - which military guns will have.
Some insist the first shot from a cold barrel is more representative of what will happen. I have no problem with that for hunting, I just question why buy a barrel that shifts the point of aim that much when warmed up, and whether it's even worth the bother. Again, a 2MOA barrel shoots a 10" group at 500 yards - hunting medium game means it will be about half the size of the 18" kill zone on whitetail deer or larger. For combat, humans use the same 18" zone.
On small game at distance, like prairie dogs, things are much more challenging. There you have 200 to 500 yard shots at 6 to 8" targets, and even a 1MOA gun at 500 yards, with a 5" group size, will miss a skinny dog standing up. 1/2MOA guns, or at least a 2" group at whatever distance the dogs are at, is the preferred maximum, and the shooter is still left with getting a powerful enough scope with enough elevation adjustment to use, plus wind, mirage, and their buddy getting it first.
What's happened in some circles is a MOA result becomes comparative and gets ranked by those who like having social heirarchies, and the testosterone challenged logic starts up with "My MOA is better than yours." Long distance precision shooters see that in their rankings, along with calling the wind and interpreting mirage, but when hunting most North American game, or in most combat, 2MOA is the standard. Most guns shoot it, just like most cars have enough power to pull away from the curb and get you to work. "Mine's better which makes me better" should be left on a competition range where the results will be posted for all to see. In forums, it's the typical braggadocio of an anonymous poster with no way to actually rate it - which everyone should understand is worthless as the pixels it's described on.
It's really all about shooter skills, Alvin York wasn't issued a sniper rifle, and Carlos Hathcock was using a milspec issue M2 .50 cal on a standard tripod when he made the reputedly longest shot in the Vietnam war. Master carpenters don't have magic hammers, and good shooters are with any gun.