2 vs. 3 blade prop

[KnotSoFast]

Hi all, I'm new to boating and I just picked up my first aluminum boat for fishing. It has a 1971 6hp Johnson and it has a two blade prop. I was wondering if it would be better to have a three blade prop. The motor runs great and was well maintained by the previous owner as far as I know. But the prop is a little banged up. If you were me, would you replace it with a two or three blade?

[boats.net]

Three blade is a better all round prop.