I bought a S&W Sport II and it looks like it will be a nice rifle. I hope to get out and zero it with the Nikon P223 3x9x40mm scope I added this week. I just got out of the hospital so I'm on light duty for a week. I think this rifle will be an excellent entry level AR and meet my needs.
I also have a DPMS AR 15 that I've had for 2 years and it eats everything and has never failed to fire. With the same scope it shoots my reloads into 1 inch at 100 yards so if the Sport II matches that I will be happy.
I'll be interested to hear of your impressions of your Sport II, one you shoot it. I'll be curious to hear how its accuracy compares to your DPMS. I know in my case, I was pleased with the accuracy; here is what I managed (at 25 meters with the irons)...
My first 3 groups...
For reference, the circle at the center of the target is just over 1 1/2" dia. -- 1 11/16" to be exact.
Ignoring the two shots to the right, with the x's in them (my friend shot those two with his rifle), the first group (the very first rounds through the rifle) was nice and tight, but low. I adjusted the front post sight, and shot the second group (which is accidentally labelled "3" on my target, but was actually the second group). Not a good group -- partially because a guy with a shotgun was blasting dirt and rocks in close proximity to the target while I was shooting!

Still, I was able to ascertain that I was now shooting high, and a little left, so I adjusted downward, and to the right. The third group (accidentally labelled "2" on the target) was "good" in my judgement in terms of windage, but a bit low, so I adjusted upward slightly, and shot the final two groups, in the next pic --
My last two...
Here, in "group 4," I felt that I probably was still just a tad low. I made one more small adjustment upward, and fired the last group, group 5. I left it at that; I'll fine tune a bit next time, when the range isn't full of other shooters.
Anyway, bottom line, I was pleased with that, shooting factory loads (American Eagle .223), and my first time shooting an AR (and first time shooting a rifle without a scope in probably 20 years!)
I was pretty pleased with these groups. Seems to me, from my perspective, that in the right hands, these rifles are pretty doggone accurate. Hopefully you are as pleased as I am, fyimo, once you shoot yours.
Steve