If you are thinking about putting a scope on the gun, I feel that the A3 is by far the better choice. However my friend who just got ou tof the Marines said to me just last night. "Why would you ever want to put a scope on an AR, I can shoot someone out to 600m with it, what more do you need. My Bushmaster is an A2 and I would tend to agree. Unless you will be using a scope the majority of the time I would Go for the A2. I think that it looks cooler/more traditional, costs less, and is more comfortable to shoot for extended peroids.