Like most guitarists, I'm sure, I have both preferred thicknesses and brands of guitar pick. I have always liked using Jim Dunlop Tortex picks, for instance, as I like the way the plastic wears smoothly. Following these I'm happy to use the generic "shiny-black" picks (e.g. Gibson picks), although these seem more prone to chipping. I don't like using nylon picks, but I can understand why other guitarists like them, particularly when playing acoustic guitar. And I definitely don't like using any type of picks from "pick-cards"; they seem barely better than yoghurt-pot plastic.

Are there significant differences in the types of plastic used for different types/brands of pick?

Are there significant differences in the manufacturing process of different types/brands of pick?