Product review (3 stars): Protects most of the burner tray
I bought these for an apartment so that I wouldn't have to replace the burner trays when I moved out.  Yes, they caught most of the cooking debris.  However, the edges were still unprotected so I had to buy new burner trays anyways.  Plus the new burner trays cost about the same as the pack of burner bibs.  These are still helpful, but if you need the entire tray protected the aluminum foil works better.