Originally Posted by bakechef
I don't care for the silicone baking mats for baking cookies that spread, like chocolate chip. The mat takes a lot longer to heat than just the pan alone, causing more spread. I baked my butter pecan cookies on one and they came out very thin, I baked the next pan on parchment and they came out perfect.
They are great for other things.
I've never oiled mine
No one has named these types of mats yet so I'm determining that what most are speaking of are the Silpat-type mats. I've never had one of those and don't think I'd care for them. They seem way too thick/heavy for my purposes.
The mats I have and have had for 20+ years are black and about the thickness of two sheets of typing paper. The original package of the mats I bought came with a couple cookie sheet-sized sheets, a 9x13 pan size, an 8-inch square, and three 8-inch rounds for cake pans. Later, I bought a roll of the stuff and have cut many more to fit most of my frequently used pans.
In fact, the 3 Teflon-coated jellyroll pans I began housekeeping with in 1968 are still in service thanks to cut-to-fit silicone liners.
As for performance, I haven't seen any differences in any of the cookies spreading or not spreading when using my mats.