While I have played BoA, I am not very knowledgable about it.
AACW's AI is pretty solid. There are a few options you can tweak that will 'raise' or 'lower' it's performance. (quotes to reflect varying opinions on the changes they make)
Naturally, like any AI, you can find consistent measures to defeat it. I find that it often responds as it should to movements of forces, both large and small. But that it does seem to not use the full potential of the game's command structure. You will find that your 'opponent' often has troops not properly led and they get penalties as a result.
While there is some debate in these forums as to the overall quality of the game's AI, I think it does a great job of making the game a great play. In particular I think if you roleplay a bit with your commanders the game takes on a whole new aspect that can be a lot of fun.
I play as the CSA mostly and my advice with them for maximum fun: play with an eye towards history, but win.

My name is Aaron.
Knight of New Hampshire