The nickel/zinc plated clamp is a more industrial-looking clamp. The bronze clamp is fancier & smooth looking. Both bend about the same & hold the same strength. The only other way to fashion a lead rope end into a circle is to braid it. Using a clamp is much easier & faster, and they hold well.
Choose bright nickel plated (shiny chrome look) for rust resistance, OR bronze plated (an alloy of copper & tin), also rust resistant.