I've payed a lot of attention to him when I've rewatched games this year.
He's a pretty bad defensive end, but a pretty good defensive tackle. On the end he gets swept out of the play and has trouble disengaging to make tackles.
On the other hand, he looks much more comfortable inside and is able to be pretty disruptive. I'd like to see more of Ayers on the outside with him in the middle (we saw a bit of that last week) as I think that is where he's going to be more effective.