I purchased these to use for mixing. They adhere well to the table & don't slide around while stirring. Cleanup is super easy. Nothing seems to stick to them. I also use one to hold beads. I love multi-use items & these really fit the bill.
I was looking for some cups to hold materials, intend to put beads and hooks on then when I am doing a few flies. I like that you can press the cups to suction them to a work surface.
Haven't used it as a mixing device but have used it for tying. I have several. How I find it useful is having the sort of hardware components separated for each pattern. As for a balanced leech pattern: One for the hooks, one for the beads, one for the sequin pins. This avoids all of those items scattered all over the tying table. Works great.
Been tying some bonefish bitters with the sparkly powders. Works great.
It works well for its use and is pretty good looking if that is something you care about. The fly tying powders stain it but it doesn’t matter. I use it more than I thought I would.