If I lived in a rainy climate, I’d for sure do the windshield.
How would it hold on top of the PPF Xpel and would it even do anything to protect the paint in SoCal weather? I already wax my vehicles 2x a year, before summer and winter and had no problems with that.
Just did it last week actually.
You want GTechnique Halo, it's a product specific for PPF, For the windshield I recommend a proper and thorough cleaning/machine polishing then coating with Wolf's glass sealant or a CarPro Flyby Forte.
Glass is a PIA and requires attention, I retreat mine 2x in the summer season and once in the winter. It all depends on your wiper use and condition. They do tend to stay cleaner longer and are much easier to clean.
Ceramics are great provided you employ the correct and necessary steps leading to using a quality coating.
It's a super hot market with lots of competition for the consumer $. Imbedded in the game are lots of fancy advertised and gimmicky "coatings", Graphine being a huge buzz word. As are most things, there are opinions and claims as to which to use, what's best and...their life expectancy and longevity. I've vetted many products, learned technique, read, re-read, witnessed first hand all sorts of car care products. There is a ton of great information available as well as even more hype and misleading information on the subject and products. Find a trusted source, ask questions, ask to see results and for customer reviews. Are they certified installers of said products? Yeah, it's a thing. None of this is cheap, even the half assed and misleading.
And, yes, automated car washes are the cause of premature failure of a properly ceramic coated vehicle. Harsh soaps (high Ph), dirty equipment,, materials used to withstand the abuse, pressure points, force. It all adds up quickly.
Convenience at a price they are.
Warranty on such things...well, with proper recommended care and maintenance, you can expect 60% of what's claimed before the properties of the coating begins to show signs of failure. They don't last forever. Installer warranties are different from the product manufacturer and they can say whatever they want.
Void the warranty...Let me guess? the installer "recommends/provides hand washing "maintenance' washes, of course at an additional cost, perhaps a maintenance package? Brilliant business/marketing technique. Again, go back to the initial cost. Those who have/want can afford to. It all boils down to what you want to achieve and maintain.
I do my own work, use what I know as quality product, employ good technique and enjoy great results. It's always been important and is absolutely a passion. One that has become my retirement exit plan.