I tried a KeelGuard on my FXHO as the first step to trying to protect the bottom from getting scuffed up going on and off the floating dock. I even called the folks at KeelGuard, and ask them if it would work going on and off the floating dock. They said yes, but mine only stayed on 1 season before it started coming loose in several places. I ended up ripping it off, cleaning the residue off, and repainting the bottom. The people at Keelguard backed the warranty and sent me a brand new guard, which I promptly sold on Ebay.
If you have one of the newer FX hulls, then they don't recommend even putting the KeelGuard on it. It will not go over sharp contours, and I think using it on the new machines would void the warranty for the guard.
I'm getting used to the scuffs on the keel now. I figure I'll probably have to repaint the bottom again in a couple of years.