Keens hands down for durability. I bought some second hand which are now on the 3rd child and going strong.
Fwiw I went to a chiropractor for some back pain who attributed it to walking around and picking the kids up in my crocs which I use as house shoes. He said it wasn't the thickness of the sole but the way it flexed when you walk. Most shoes follow a curve like pattern, crocs just jackknife.