:smt042 I'm getting too old to polish for no reason. These muscles and joints need a lot more rest than they used to.
Polish with Sealant does a very good job of removing stubborn wiper streaks, water spots, and squashed insect remnants from windshields. It also leaves a nice slick surface which sheds raindrops quite efficiently. It is also my primary paint polish. When I machine polish the paint, the last thing I do is run the buffer over all the glass panes and window frames. It saves me the trouble of changing out to a different pad and polish just for the glass surfaces.
If you are dealing with deeply etched water spots (like those due to acid rain), I might opt to go with Pro Polish or Pro Polish 2.
P.S. I noticed that your location is Denmark. I have visited the Scandinavian countries twice and would love to return for another trip. If the currency exchange rates with the US dollar weren't so poor, I'd visit a lot more often.