My phone had a deep scratch in it from one of my nails. When I ran my finger over it, I could feel it. I had another more shallow scratch that I couldn't feel with my finger. I bought this stuff knowing that it could be a bad idea to use on my phone and did it anyway. It worked. The deep scratch is and will always be visible, but I can no longer feel the bumpyness of it with my fingertip. The other scratch is completely gone.
This product isn't too messy, but the moment I opened the tube for the first time, it did spill onto my fingers, so be careful. It's still totally worth getting though. You don't even need a lot of the product for it to work.