My #2 DD does a fair amount of shoping at AE
It's an OK brand for the high school set to be seen in.
DD wears AE jeans, while the same is not true of most A&F jeans, which seem to be cut really tiny.
My oldest DD, who prefers a more baggy look, has found things that work for her at AE as well.
I'd say they both tend to buy about the size you would expect at AE, maybe a size up depending on the style. Otoh, we had to take back A&F stuff I bought for Christmas to get bigger sizes.
My 8 yr. old DD actually fits perfectly in one of the small shirts I got A&F (and no, it was not from the kids store)
Some of that stuff is miniscule.
Like the others have said, quality seems to be typical of a lot of stuff geared to the teen market. Not horrendous, but I wouldn't expect it to last for years either.