I disagree this thread has lots of perfect I formation about a few of the buildings. It's a quick reference.
Avaries earn a bit less plunder an attack. But they get more attacks per regen (allthough the rate is the same) so you'll more if you crystal or if you cant get on every hour. Circles make a little bit more; but like an avary, the difference is so little even with full circles you wouldnt notice the difference.