I got to shoot an AR-15 M4 style and an AR-15 A2 style today.
Hated the M4. It had a red dot but wasn't very accurate at all (not as accurate as my Saiga). I won't say the brand as I don't want to crap talk any particular brand. Owner has tried a variety of ammo, and it just isn't better than 5" groups at 100 yards with any of them.
But aside from that, seems too small to me, don't like the tube feel of a collapsable stock tube. Don't like the short hand guard. Even started to burn my finger because I shoot with my hand far forward and it was touching the barrel.
But the A2 I loved. It was a Colt with a Bushmaster stainless 16" heavy barrel using the the full length A2 guard, full length sight radius, too, I believe. He said everything is exactly like the original just that the barrel is shorter. Supposedly Bushmaster made those barrels for the A2, not sure if that specific type fits the M4 (I don't know about this stuff). Fixed handle, and what I assume are the standard AR iron sights, rear peep, and front post in the middle of a front curving v type pair of blades. I found the blades help to center the front sight inside the peep. I shot 1" groups at 50 yards. A lot better, by far, than what I was able to do with the M4 and its red dot.
I don't want to get caught up in the accuracy differences. I just really liked the feel of the A2. A lot less recoil, better fit, even seemed a smoother action.
Yeah I know, it is just a sample of 2. But gives me some ideas of what I like and don't like between the configurations. Please keep in mind that these opinions are just based on my own range preferences. There are real world uses for these guns that could show me different priorities and purposes to consider.
Too bad the A2 was firmly "not for sale"
Oh, no jams