I currently own 4 AR style rifles, 1 Colt HBar set up for long range varminting, 1 box stock Colt SP1 'slick side' circa 1981, 1 SBR 10.5" built as a minimilist 'tac' build and a Bushmaster M-4gery that I bought stock. I then commenced to put the 'tac' accessories on it that I wanted,
(let me stop here and say I am not LE, never have been, just a true firearms enthusiast, not a 'mall ninja' either, I just love building and shooting firearms, and I really dislike that word 'tactical')
I had in mind all the features I thought would look 'right' and over time acquired and installed them. When it was complete I had a very versatile rifle, looked great, shot great.
I also spent a significant amount of money getting it there. I love the hobby tho' so that is just a part of it.
Soon after I had completed the Bushy, S&W came out with thier version of a 'tactical' carbine that had just about everything on it I had just spent months and many $$ putting on mine. For about half of what I had in the mods made to my Bushy!
What I'm trying to say is this-if you want a box stock AR, I think both are on a level playing field, if you want to go the route I went and build it up, by all means go for the S&W in the preconfigured mode, it will save you a whole bunch of cash. If I were to do it over again, that is the route I would go.
Of course if you love to build and tinker like I do, then either way you can't go wrong, just make sure you have a really understanding Spouse (mine is taken, move along).
RD