Berghia Verrucicornis are indeed a cinch to breed, and a article detailing such is in the archives a few months back Reefkeeping Online Magazine: http://reefkeeping.com/issues/2004-0...ture/index.htm
The biggest issue I have found is that they do not find every aiptasia either, but rather as the aips disappear so does the population of Berghia. The aips then are able to make a comeback (and thus the Berghia population rebounds as well). I have yet to be able to study any long term evidence of if a side ever eventually wins
. It would really depend on the size of the tank. If the tank is small, the Berghia could probably wander and find the last ones before starving and thus be very effective. However, if used in a larger tank..that is quite a bit of real estate to happen upon remaining pests.