Our experience has also been from Category 2 - great view even from (maybe because of) a high row.
A purchasing tip - go to mousesavers.com and access Mary's link to undercovertourist.com. The price that's quoted includes taxes and shipping and you'll save a few dollars from the box office price.
Undercover Tourist will send you vouchers for Cirque tickets and instructions on how to redeem them - just go to the box office at least an hour before the performance and they'll process the vouchers and give you tickets for seats in Category 2.
Dick Taylor