Well I'll agree to disagree on that one. I've been running Rain-X pretty much since it came out way way back before they even made Rain-X washer fluid. I have never had a single issue with a washer fluid pump from Rain-X. Somebody would have to be literally holding a razor blade vertical to scratch a glass especially on newer vehicles with the more resistant windshield. Holding the blade out about a 10 to 15° angle and scraping the glass like you're supposed to yields absolutely perfect results and zero scratching. Again with the Rain-X there is definitely no buildup on the windshield whatsoever as a matter of fact if you apply Rain-X and don't use Rain-X windshield washer fluid regular washer fluid will completely remove rain-X in about 5 to 6 months use if you supplement it with washer fluid you'll get well over a year before you need to reapply the windshield treatment. Same goes for aquapelle treatment. Buffing in a good wax works also personally I don't find it works as well as the windshield treatments. And yes ceramic coating does work also but usually way more expensive and will still need to be reapplied down the road adding to that expense again versus a $6 bottle of Rain-X windshield treatment that lasts about 15 applications.
It never fails that the guys that are dead set against Rain-X and Rain-X washer fluid are almost always car detailer guys that are promoting ceramic coatings. It's funny 10 years ago before ceramic coatings took off Rain-X and aquapelle were heavily promoted by detail guys especially aquafel as it was a tad bit more expensive so it could be sold at a higher premium.
I don't even have my truck ceramic coating so no, I am not promoting ceramic coating ... quick to assume ...
You are telling someone who probably has never used a razor blade on a windshield to use it with a higher risk of scratching it ... the most simple and safest method is to use a claybar kit, clean it up with either 80/20 IPA solution or water vinegar ..
That same bottle of ceramic coating can be used on his wheels, on his headlights, for so many things and it doesn't have to be an expensive brand of ceramic coating lol ..
I don't promote a single product as a detailer, I don't even let customers know what I use especially when it comes to coatings, waxes or cleaners.
But by all means go ahead and disagree lol, I am the one that gets called to polish up a windshield that was scratched up by razor blades and my starting price to polish a windshield is $300 and that's because a lot of people don't want to replace their windshields with non OEM ones, so they have no choice in the minds than to pay to get their windshields polished...
Again, my method and recommendation is the safe one, proven and will last years and the most it will cost you is $20 for a claybar kit and $50-$75 for a bottle of ceramic coating which can be without having to call a detailer or going into a shop ... tops $75 and you don't risk scratching up your window, clogging your pump.
Have a good night kid ...