I very much enjoyed Army of Two. This has been by far the best Army of Two game. Weapons were better and more customizable. Graphics were very good, music was good, gameplay was good. I enjoyed the story and even started playing it again in a harder difficulty level.
Army of Two has always been kind of a meh series for me. I do enjoy playing coop online with friends though. Unfortunately, EA has decided to tie the newest installment into their money-grabbing online pass system. Since I won't support having to pay to play online on top of my xbl sub I guess I won't be playing this one.
If you buy it and can play online or just want to play single player then give it a try. Otherwise, pass on this one and go rent a better shooter that doesn't make you pay extra for the privilege of playing the full game.