Not sure why anyone thinks you can argue with the Colt guys.
However to answer the OPs original question, there is a ton of good and not a lot of bad with the 6920. Great basic, out of the box rifle. Just depends on what you are looking for and what you want to do with it.
If you don't want a carry handle, budget for a rear backup sight. If you want a quad rail, research them first and factor the cost. If the A2 sight bothers you because you want to add an optic and don't want it in the way, budget for a gas block swap and front folding sight. If none of this matters and it's exactly what you are looking for, then you are GTG with the Colt. Very well respected and proven gun. Best of luck!