We put solid walnut in our dining room a few years ago and it's plenty durable. We don't have kids or dogs, just a cat and furniture. But we've been happy with it, and just put it into our family room.

I had engineered walnut installed only a few weeks ago so it's premature to comment on durability, though an aluminum oxide finish is supposed to be more durable than poly. It was installed in a room that doesn't get much traffic, but it will also be installed in an entrance room in a few weeks. Time will tell how it holds up. It was a difficult decision to make since so much flooring today seems to be "exotic" woods, handscraped, etc. I preferred something more traditional. The flooring looks beautiful and I'm pleased with my decision.

A quality engineered product will have a wear layer that can be sanded at least 4 times by a professional. Brand examples; Owens and Real Wood Floors plus others. Look for a cut, not rotary veneer and a thickness of over 1/4 for the veneer.