3m polyurethane sealant 550

[Isaacm1986]

So I am wondering if anyone has ever used this 3m polyurethane adhesive/sealant 550? Says in the bottle it has great adhesion to aluminum, and to use above or below the waterline. I am wondering if there is a big difference between this and the 3m 5200?

I was at the marine shop picking up some 5200, when I saw the 550 sitting next to it.

Thanks guys.