We went when my DS was 6. We absolutely loved it! We got the better level seats -- I think we were 5 or 6 rows up, center -- and it was great to be so close to the action. My DS still talks about it!
It was well worth the money. It's hard to describe Cirque -- there were arial, trampoline, and bike acts, and a lot of things I can't even name. And those juggling girls from China were phenominal!
You have to see a Cirque show at least once, and this is a great one. Go and enjoy!