Basically, At Close Quarters (ACQ) delivers alot less than it promises. While the rules are intended to streamline the combat system in Traveller and make the effort more "realistic," it seems to me that the original system (which I have never played, but which I have read carefully) is easy enough to work with and needs no streamlining.
In terms of accuracy, I am willing to allow that I may have missed something, but ACQ didn't do anything for me. What Traveller (and most of the other reconstituted and updated GDW titles as well) needs is a clearer explanation of when, where, and how combat would be conducted in the future. Once the basic premises are filled in -- as they would be in any military RPG (such as T2K), almost everything else falls into place.
I have seen worse and I'm not sorry to have purchased the product. It just didn't provide what I was looking for.