Last year I wanted to book a trip Toronto to Las Vegas, or LA. With exactly the same flights I could use either US Air dividend miles, or AE.
Booking with AE would add more than $200 to the tax/surcharges. Of course I ended up using US.
The one good thing about AE is the longer expiry time. If I have a choice to earn points, I'd earn on other *A programs rather than AE.