I have a Pulsator, I have used it twice.
First Time I used it was in a tank that had quite a bit of grass and weeds. The pump sucked in grass and trash and it stops working.
The Second Time I used it was in a large tank with a pretty muddy bottom. The case that is provided to hold the battery got stuck and I had a heck of a time getting it to come up.
I did not see in any added benefit to using it and the bubbles that it produces do not seem to move the other decoys as much as I would like. Also, they decoy and all the stuff that goes with it weigh about 15 lbs, when transporting them.
I bought two of these after the Pulsator and I am pretty happy with them:http://www.therealdecoy.com/feeder-duck-decoy.php
They are also about 1/3 the cost.