Mars has a few holiday M&M varieties on the market. One version is peppermint & milk chocolate. The other is mint and milk chocolate.
The mint milk chocolates had a smooth, cool mint flavor. The peppermint candies were another story. The peppermint bags had a mint smell but almost no mint flavor. The mint flavoring in both varieties tasted exactly the same. There was no difference in the ingredients listed, either.
I would buy the mint M&Ms again, but not the peppermint M&Ms.