One thing I should add, it took years for it to start to attack the rubbers vs Krown or Rust Check that swells within a couple or so years.
As for it's rust protection, my '16 Ram is spotless underneath.
Places to have it applied, two of their most highly rated shops actually did the worst job. At a glance looked fine but once up on the hoist clear to see anywhere that really mattered was dry as a popcorn fart. Another member here directed me to a small shop in Oshawa that have been doing it properly.