I got a bottle of this product from a friend and tried it on my flybridge glass that had become extremely water spotted/stained. No glass cleaner that I could find would take the spots away. I sprayed Ducky Water Spot Remover on, Waited 10 seconds, wiped with a damp chamois, and the spots are gone. My next trip is to West to buy a new bottle or two and finally get the glass clean.
I too had hard water spots I could not get off with any glass / window cleaner. Used this and it worked as advertised. The only had thing is that its an orange liquid that when it gets on your hands it will take some scrubbing to get off. Not exactly sure if its removing my wax job at the same time?
I used the original for years have alway been happy with the ease of this product not to mention it works well, I have since found that they have one with wax that works just as well and gives my ski a nice wax finish. I also use this on my shower doors love it.