I have heard both, but not in the same system, so my conclusion could be off..
However, I believe that they both offer quite different presentations.
The Wadia presenting a more technically correct sound, the AA more musical, but probably rolled off at the freq extremes.
A lot would depend on your preferred sound. Do listen to both, since they both sound SO different.
I would go with the Wadia... because that is the sound I like.