Ebony the hardest and would last the longest. Rosewood slightly softer, but still very hard....and Koa would be the softest. Others are more qualified than me to comment on it as for fretboard use. I prefer ebony for cosmetics as much as for durability, but I also like ebony bindings, headstock veneer, bridge. Unless you are going to play mostly one instrument for long periods of time, frequently, you are not likely to wear out any of these three in your lifetime.
Of course, this is just my take on it.