Wow! I have never seen these before, Leisel! I, too, look forward to the feedback of those who have used them.
Hmmmmm...interesting. I've not seen these before but I'm sure curious about them. I have a silicone mat that fits my large baking sheet and I don't really like it. Since I have good baking sheets my cookies do far better without the silicone mat, but I'd love these rounds if they don't affect the baking yet allow for easy removal from the pans. I get tired of cutting out parchment rounds for the bottoms of my pans.
Country Kitchen sells precut parchment rounds for baking - I have the 10" ones, and love them.