The powerbass is a good price my cousin just replaced 2 of his saz2000ds with one bc3500d and claims that its louder.. well maybe because he's running the amp at 16v.. but IMO i would go with the cresendo for 599 shipped.. but against the aq3500 ehh the aq is super under rated it does 4300 at 1ohm.. so yeah my . 02
Sorry about typos im on the phone..