I had a comp stock replacement collapse on me. Just out testing one day and BAMN, my valvetrain sounded like a sewing machine and I lost power. i had a 640ish lift cam in her. Now I am running the caddy lifters and they seem to be fine.....with a smaller 590ish lift cam.
BUT.....I am switching back to the big stick, so we will see how the caddys hold up.