Product review (5 stars): Great, but make sure you really clamp them
My rental house has granite counters but the dishwasher is just kind of sitting there. I've dealt with the dishwasher falling forward for 3 years now, and finally I though to try and search out a solution. I was about to use some liquid nails and a thin wood strip when I came across these and figured for the price, they're worth a shot.

I cleaned underneath with my usual granite cleaner (rubbing alcohol, water and a drop of dish soap) and excitedly applied the grabbers. I stuck them on and put a spring loaded clamp onto each for 5 minutes as instructed. Actually I probably left the clamps on for 15-20 minutes. After a few hours, however, I noticed they were starting to pull away a bit. Uh oh. I was concerned because the instructions mention a 3 hour cure time, and I was about there so if they were already cured I was in trouble. But, I clamped them up again, this time with two spring loaded clamps on each one (on either side of the screw). I left the clamps on overnight. That was a few days ago and as far as I can tell they aren't coming off anytime soon. If I remember I'll update this review in a few years and let everyone know...

So upshot: cheap, easy to install and work great. Just make sure you clean the area really well, and get some good pressure on them with clamps and leave the clamps on longer than they suggest.