I personally use one on my bass boat, I like it. I have tried the boat both with and without the foil on, and found that it plowed really bad with the foil off.
Now my boat is set up with dual tanks, and three batteries, all of which are located in the back of the boat and very little weight in the front of the boat.
I have the same one, on the SE sport clip since I didnt want to drill in to my lower unit. Actually its my second one, the first is at the bottom of my lake....it came loose one day and fell off.
It helps me with porpoising and more control at low speeds.
Very polerizing subject that has been covered a couple hundred times here, kinda suprised noone has chimed in about smart tabs yet.
I run a homemade one on mine which is a copy of one I saw in Cabelas made from 3/16'' aluminum and it works really well but depends on the boat, some run better some run worse but as JB pointed out it is a different deal now and you will probably have to tinker with engine height and trim to see if it's really better or not.
I am on plane alot faster and can run lower speed on plane with, some say it puts stress on the engine mount but I have run mine for 9 years with no problems at all.