I have used both a metal loop and a string loop and really don't see any difference between the two other than what 5-shot said, the price. I used a metal loop for 3 or 4 years, then switched to a string loop and have been using it for the last 3 years. I hear a lot of people on this board say that the metal loop will damage the serving, but I never saw where this was a problem. Either one you choose will work fine.