My preferred Thor 'super plastic No.2' hammer with a nylon insert one end. This has deformed slightly over the years but hasn't marked the spinners at all.
The MGOC hammer described as 'lead faced',
whatever that means. It is very shiny and extremely hard,
in fact it wouldn't surprise me if it wasn't lead at all but some harder alloy. Just one gentle knock far lighter than required to undo the spinner was enough to mark the chrome.