I bought some el-cheapos from china off ebay and they lasted about 2 years. Junk.
I've got a friend who owns a business here in the Detroit area, and brings in headlights from around the US, polishes, and resells. I'll get an honest opinion of how good they are. They can polish yours also, just would need shipping both ways. I can do the handling and inspection on this end for you if you are interested.