If you were looking to buy your first AR, or if you're looking to add a new one to go with the one you have, I'd say get one of the Colts mentioned above.
If not, you already have a reliable AR, that isn't likely to be any more or less accurate than one of those Colts. You might take some time to do some checking the gun and tuning or replacing some parts.
http://www.m4carbine.net/showthread....w-better!-quot