I have not used them, but they look pretty good to me! I have a mat that I put down in front of the SI to catch any drippings when I am putting meat in and taking it out. I definitely recommend having something in front of the smoker for this reason.
Those look like they'd be great for covering standard shelves, for jerky/fish/small stuff. I'm considering ordering! Thanks for sharing - I'd never heard of these before, but have been looking for other options to do what I mentioned.