I'm a believer! I had a 2005 Bennington that I ordered WITH Sharkhide applied by the factory...it was like a $375 option then, and well worth it then. It kept the pontoons shiny for six summers, and was a real selling point when I sold the boat last fall.
I picked up my new boat two weeks ago (a 2011 2275 RLi), and spent last weekend cleaning up the pontoons to apply Sharkhide by myself this time, since you apparently can't get it done by Bennington any longer.
I hoped that I wouldn't have to spend much time cleaning up the pontoons before I put the stuff on, but I was wrong...It kind of looks like my boat must have endured some road salt on the ride from the factory to my dealer, so I used the Sharkhide polish (not the cleaner) to shine the pontoons up first. Although I have some swirl marks from the polishing, they're good enough...and you can actually see your reflection! I have one coat of Sharkhide protectant on the pontoons now, and will get a second coat on by the end of the weekend.
Hopefully, my efforts will last five or six years again!