I too would recommend that you build it if you feel comfortable with it; but I'm assuming that due to the fact that you are new to the platform you would rather buy a complete gun, or just stick a upper on a lower. I recommend sticking the upper on the lower.
Maybe a BCM rifle length upper with a rail system
, a Chromed BCG
, Charging handle to meet your fancy, and a Rock River Arms Complet A2 Lower With or without the NM trigger
. The BCG and charging handle go into the upper easily without tools, and the upper goes on the lower with the push of 2 pins. Also it A 18" barrel should fill most any needs you have. With practice you can go out to 1000 yards with it, the 1 in 8 twist works well with everything from 55 grain bullets up to 80 grain bullets, the heavy profile barrel also helps, and the extra 2 inches of barrel length doesn't make that much of a difference. The setup I suggested comes out to about $1200, and will serve every practical purpose you can think of; including looking cool
Good luck picking or building your new rifle. I hope to see a "I got a new rifle" post from you soon