TK, S&W has two new M&P15 models, the Sport, and the new version of the M&P15T (SKU: 811041).
The Sport comes with handguards that lack heat shields, so factor in $20 or so plus shipping to replace them with shielded handguards. The Sport also lacks a dust cover & forward assist, and is the only M&P series rifle to do so, but you've used M16s / M4s so you can evaluate the necessity (or lack thereof) of those two items yourself. At $600 or so street price it's still the best buy on a budget rifle.
The new 15T has the same Troy quad rail as the old one, but has switched from the expensive Troy back up irons to the more economical (but still very high quality) MagPul MBUS back up sights. The new 15T is selling for under $1000, which makes it the only other strong value from S&W right now.
The kicker is that these two models use S&W's new Melonited 1:8 twist 5R rifled barrels. The 1:8 5R rifling is showing itself to be very accurate with just about any bullet weight you can feed an AR. S&W's Melonite (aka Black Nitride) is done by the same contractor that does LWRC's Black Nitride. This is a surface hardening process which produces a very hard, slick, durable part. LWRC claims their testing has shown Black Nitride barrels to be more durable than hard chromed. Because you don't have to overbore and build back up to correct bore diameter as is done with hard chroming, you eliminate potential accuracy loss by Nitriding.
S&W individually HPT / MPI each bolt, uses the mil spec buffer tube (instead of the weaker commercial type), and they properly torque & stake everything. In short, they assemble all the M&P15 rifles like the big guys do.
They don't HPT / MPI their barrels, but the bolt is the far more critical part to do this on. They also use 4140 steel on their barrels rather than 4150, but in a semi auto this isn't really critical. Because they make a very good bbl, assemble the whole rifle correctly, and only cut cost in non critical areas, the M&P15 rifles can still be run hard like the top names.
As for Daniel Defense, I currently own a DDM4 v1. I've owned Colt, LMT, Noveske, and some lesser brands. The DD is just behind Noveske for the nicest out of the box, ready to go AR I've owned. I'd buy DD again in the $1000 to $1200 price range before buying a Colt or LMT in the $900 - $1100 range. Not by much, but it still would be my choice. The key differences in the DD rifle versions are carbine or mid length gas, fore end (M4 handguards, various DD quad rail types, or DD tube with modular rail attachment), and standard M4 contour bbl or lightweight bbl. The core of their rifles is the same throughout the lineup. They're all great quality, so just pick the version that best suits your wants / needs.
If you can't get a DD, then LMT is still an excellent option. I also purchased an M&P15 Sport as a good quality, low cost backup to the DD. Or so I thought. After a handguard upgrade, and shooting the Sport more I realized what a bargain it is. It's not a DD, but it's amazing how well it compares at several hundred $ less.
Hopefully this long winded post was helpful & informative.