I like metal frames. The chops at Michaels and Hobby Lobby are a nice extrusion. Michaels has the shinny black painted ones and Hobby Lobby has the more matte anodized ones. Not being a volum buyer (yet) this is the easiest solution for me. It helps to know which day a shop stocks its chops as if you just wander in there on any given day they may be out of the very one you need.