Folks, before you spend a bunch of money on a rifle do some research and see what your getting. Sig(556 is particular, 516 is ok), DSARMS, Ruger(still way to new for that kind of money, many issues so far), Bushmaster(good back in the day, now not so mcuh) are all essentially junk. You can get much better rifles for your money.
For 2K,
Larue OBR
http://larueosr.com/lt556-16.aspx
Damn good barrel, nicest battle trigger you can buy, billet upper and lower, magpul stock, nice rail, other accessories are excellent. Best DI gun for 2K IMHO. Noveske is nice but you have to spend a touch more than 2K and you still won't get that wonderful trigger.
For piston,
LWRC M6A2
http://grabagun.com/long-guns/ar/lwrc-m6a2-556nato-16-rail-piston-30r.html
LWRC is the place to go to get piston rifles. They do the piston right. So much so that Sig completely ripped it off for the 516 and is getting sued for it. The barrels are nitride treated and BCG are NiB treated, as well as the FCG. Nice rifles for 2K.
Personally I think piston AR's is a solution in search of a problem. DI works well, just don't be lazy and clean your gun every now and again.
If you sped $1200 on a piston rifle your just shitting yourself. Your getting a low rung piston rifle when you could have gotten a quality DI rifle that will provide years of troublefree service. For $1k you can get a Colt SP6920 which is dead nuts reliable and as high a quality gun as you can get for any price. Sure, it doesn't come with any tacticool accessories but you have a quality base to build off of. Myself, I am a Daniel Defense guy. A bit more money than Colt but the addons are worth much more.
Bottom line, do some research and know what you are buying before you drop north of $1k on a piece of shit.