Never used one--I personally carry either a sissor jack or a 4 wheel dolly jack for the trailer--plus several hyraulic bottle jacks and some blocks. For example with the 25, the bow strap broke on the first launch when the boat was 6" from the stop--so we jacked up the boat, and moved the trailer under the boat until it was properly supported. (The trailer dealer put a 1500 lb strap--we now have a 4000 SWL stap..
I guess I just don't trust that kind of "jack" for a heavy boat. It looks like it would be easy to fall off of the "jack".
