I recently bought RRA's Elite CAR A4, my first AR, and I could not be happier. Very solid, no play between the upper and lower, and the best trigger I have ever come across, period.
Added an Eotech to the flat top and a Harris bipod for the range. Also, bought a Ceiner .22 conversion kit and now I can shoot all day if I want -- without breaking the bank. I highly recommend the kit for indoor range fun.
Before buying the RRA, I never considered a Colt, due to the cost and went back and forth between a RRA and a Bushmaster. My best friend bought an Entry Tactical (M4 clone) and was very happy with it, and everyone else I spoke with had nothing but praise for RRA, so an Elite CAR A4 was a no-brainer for a guy looking for a solid mid-length. Also, the deal I got from Eagle Firearms could not be beat. Hope my two cents helps.