I have experience with Yellow tangs. They are very territorial and can cause problems if they are added before less aggressive fish. I am working on restocking my tank and looked at a Kole, but the wife wants more color. I have always heard good things about the Kole, but I would not recommend what I have not kept before. Hopefully other reefers will post their success with Koles or any other tang, Purple, Convict, Chevron, Sailfin, Naso, .... the list is endless.
Jesus said "Follow me and I will make you fishers of men".