I prize functionality, durability, value, and minimal adverse impact on the environment. Since all shoe horns work pretty much the same way, functionality is not a differentiator. Since shoe horns do not seem to wear out or break, durability is not much of a differentiator either, but steel seems to possess a largely theoretical edge. With regard to value, free is pretty attractive. With regard to adverse impact on the environment, I find plastic the clear loser. Since it is already in existence and requires only refinement, one can make a case for horn edging steel out for the win, but the use of power tools to shape horn may be much greater than the stamping and shaping of steel. However, I have never received a free horn one. So for me steel wins. I got one from Shoemart. When I order new shoes, now quite rare, telling them I do not need another shoe horn seems to work. The good folk at both Shoemart and Quoddy seem quite good at actually reading comments.