I finally exhausted my 3-year-old stash of FEP film last night, and had to shop around for replenishment. Found quite a variety on eBay, all 0.15mm, the only difference I could discern from the dozens listed was sheet size. The "official" AnyCubic FEP was stupid expensive, and only available in 2-sheet packs. A number of listings specified certain makes/models of printers.
Then there's "nFEP".
The brand I have been successful with is still available, but only with shipping from China. So I pulled the trigger on a US source of seemingly generic FEP for $3/per. I guess we'll find out soon enough.
Is there a difference to consider? I would guess that there are very few manufacturers of the film, the only end-user distinction being sheet size and packaging.