They are not cheap, but I have seen them in action, very nice. I called them awhile back and think the price was like $100 or $150 each... It is an option on the 2013's. If I was not selling my boat I would add them, definite on my next boat. They have a post build installation system, you just need to make sure you know the best place to put them before drilling holes.
As far as the fender/bumper debate, we call them both by name
Fenders become bumpers when/if you come into the dock to quickly