Personally I have very good luck with the Sicce Voyager Series of pumps, which are AC. You can buy their wave controller and will allow you to customize the flow in your tank, to a point.
I just jumped into the Sicce DC X-Stream wave pumps. They are more expensive but work very well, and if you upgrade to a Apex controller, they are compatible with the use of an auxiliary cable. The DC pumps really are the way to go.
The nice part is that the Sicce's come with a 5 year warranty. They are not the Cadillacs in the field, like the Vortech's, but are a good value for the $$.