oh dear, lol, i used to use that stuff all the time, or sumthin very similair anyway, its good to use on ur front windscreen, and like u say u dont need to use ur wipers, but after a while u will need to use ur wipers and they will simply smear the water so u cant really see much, due to the waxy kinda stuff left behind by the stuff u applied, part from that, good stuff, lol
Matt