Chris,
I will be honest with you. I have owned two Sig 556 rifles. One Classic and one SWAT. The barrels on each of them are really nice, and the piston action is very good as well. BUT... that is where the good things about the rifle end. The stocks that ship on the rifle are very cheap and wobble (don't lock up very tight). The sights are very poor and are of airsoft quality. The rail systems that come on the SWAT (unless it is a Samson or Troy replacement) are very poor quality and are out of spec.. You basically have to buy a real Swiss stock, aftermarket rail, and aftermarket sights to improve the gun. That will cost you $600-700. Not worth it.
For $1000 on a top notch entry rifle, take a look at the new rifle from Palmetto State Armory. They have a new rifle for $999 that comes with an Aimpoint Pro optic included. That is unheard of. They make a top quality rifle for an amazing price.
Bravo Company, Daniel Defense, LMT, Colt, etc all make great guns in the $1000-1200 price range.
If you have your heart set on a piston rifle for $1000-1400, then check out Ruger, Sig 516, Stag model 8, or the Smith and Wesson PS. For under $2000, check out the LMT CQB Piston ($1800), LWRC M6A2 ($1900-2000), or LWRC M6A2-S.