A combat weapon optimized for ruggedness and durability doesn't inherently have "fit and finish" the way an engraved Belgian Browning shotgun has fit and finish. The AR you could leave in the bottom of a canoe and wipe down daily, it wouldn't matter. The Belgian could lose 40% of it's value after the trip.
Between the two brands, the best way to assess which is better for you is to get a large blow up of the roll mark on the lower and examine it carefully. Which looks better to you? Does one have weak artistic elements that might lead to it being thought the lesser rifle? Is one speaking to you as the dominant style aesthetic that communicates what you want others to see when you use it?
There's not much else between them to compare. They are both good rifles, it's a choice of which roll mark you prefer. Especially in light of the fact that the S&W would do the same job and deliver the same results for much less. Since S&W doesn't make the grade, then pick the better of the other two. You can only satisfy a personal perception at that tier, the guns are pretty much the same functionally.
It would be nice if a thousand guys had one, then the other, and reported back in concise numerics telling us how many rounds to failure, which fed more kinds of ammo, etc. That information isn't out there, tho, or at least those that know aren't talking. All you can get on the internet are props from happy owners or long rants from unhappy ones, and even then you have to read between the lines. "My gun won't shoot cheap import or surplus ammo!" isn't a valid complaint when the gun was designed to fire top quality military loads of just one type. Those guns are reliable, it's the operator's error to use junk in them.
Since money is no object, pick the one you like more and shoot it. Doesn't get any simpler than that.
