I've seen some of the hardest hardwoods such as Ironbark look trashed after a few short years because it was not taken care of properly.  All Hardwoods Will Ding, Dent, and Scratch.While it's true harder hardwoods are more resistant to damaging, they will still ding, dent, and scratch under the right conditions. My feeling has always been buy what you like and take care of it. Looked at from another perspective, years ago nobody talked about hardness. Then it was pine, oak, and more pine and oak.  Today they still represent a large portion of the floors people buy for their homes and they last!