I've used it a bit. It works pretry good but it is a coating not a dye. Basically paint for fabric and leather so it will wear off.
I used "Pacific Blue" for the headliner in my Barracuda. It took several light coats to cover completely and evenly. It was sprayed over a lighter blue. Turned out OK. No one notices and it hasn't worn being a headliner. I was a little leary about it maybe plugging the small headliner air holes in the thin, stretchy, vinyl like fabric but that didn't happen. What are you planning to coat?
Years ago, when I first got my roadster going I used a narrowed rear bench seat for starters. It was covered in an OE tan vinyl. The black SEMS went on great, and only wore through in a spot on the seam welting, from getting in and out . Follow the directions, it has to be clean, clean, clean. Lasted well enough until I put a Glide seat and fresh interior in it.