There are some knock off Mitsubishi and Korloy inserts out there. The copies are very good in deed. The only difference was on the Ali inserts, they were not quite as shiny as the real deal ones. On the coated inserts, they did not last as long. For a home workshop, you will not notice the difference with the coated inserts. The Ali ones did seem to get a buildup on the cutting edge that the super shiny ones did not seem to be getting. The Mitsubishi people were out here in NZ last year investigating the knock off product and what it all looked like.
Mitsubishi, Korloy, Kyocera ,Kennametal and Sumitomo , are the main insert companies I get my inserts from. They all have good stuff and pick and choose what I think is the best that suites me. For example, the Sumitomo positive geometry PCD insert I trim my Ali pistons with, is by far the very best insert I have found for the piston trimming.
After looking at the link above/below, they do look very much like the real deal, especially the Ali inserts. They look to have that mirror shiny polish on them.
Interesting for sure.
Neil