The S&W is pricy compared to the Bushmaster, and the rifle is made by Stag Arms for S&W.
I'm happy with my DPMS, way less than half the price of the S&W. Of course, I'm even happier with my Sig 556 which as pricey as it is is still less than the S&W.
IMHO, you're paying a lot for the S&W name without getting more value for the money.
Paid a little less than $1200 for my Sig 556, had a barrel and Wolf ammo issue, but Sig made the barrel right and I don't shoot Wolf.
The M+P 15T was between $850-950. close call on that one. The DPMS, if available, are harder to get in stock (here in NC anyway), good choice as well.
the XCR has interchangeable capabilities, and a Bushmaster is what it is always has been. All good choices, the prices will only go up from here. Fondle them all, find a weight that works for you and research what you want out of this type of rifle.
I really enjoy my Sig with an optics package, the M+P has better factory sights but some type of optics is better.
Good Luck, post pics and enjoy whichever one you choose. Stock up on ammo, or reload.

GunsAmerica has the Sig 556 for $1400 and up now. They will all only go one way in cost.