I have not been, but I'm planning to take my 2.5 year old. I do know that it's much smaller and far more low-key than Ringling Bros. And more importantly they have a far better record for treating their animals humanely (they only have horses and dogs).
Interesting. I live just a few minutes from the Circus and DH is dying to go, but I figured it would not be truly kid-friendly for a 37 month old and a 12 month old. Hmm, we may have to check it out.
Growing up, the company my dad worked for rented out the Big Apple Circus every year for staff development/family fun. It's awesome. The one ring is really much easier to watch and everything is so much more intimate and closer and you feel so engaged. We went yearly from toddlers to teens and always had a great time.
Re: anyone been to big apple circus in Dulles?