I think it is a good alternative if you have gelcoat that is so badly oxidized that you can not bring it back by compounding without removing most if not all of the gelcoat.
I know people who use this on an older Bayliner, they redo the application a few times per season. The boat looks very shiny, and looks very nice, you would never say that it is as badly oxidized as it is. It takes some work though.
I'd say if you can compound, polish, and wax, and the boat look half decent, then I would stick to that.
Shel