I used to be in the business.
There is a lot of misassumption about windshields since most don't replace them frequently.
1. There is a great difference between certain companies usually OEM suppliers for US, Euro, or Japan cars and generally lower quality aftermarket or China OEMs suppliers.
2. Generally in the USA/Canada, the OEM companies make excellent glass for aftermarket, even if they are not the OEM for that model.
Good glass comes from Pilkington (LOF,XXX,Triplex,United L-N,LIbbey Nippon Glass, etc.), PPG/PGW, Carlite (Old Ford glass business), Sekuirt/Saint-Gobain, Guardian, Asahi/AGC/AP Techno) and aftermarket company, Viracon.
Most of these companies with exception of Viracon, make their own glass, but it is all very high quality. Viracon buys glass from the others. Any notice of more/less wear has nothing to do with the glass or hardness, but driving conditions.
3. OEM glass for European or Japanese cars is no better/worse than glass made by the above companies’ if they are not the OEM. Major difference is that aftermarket will not have the car maker’s logos in the glass vs. OEM brand - that’s it. Glass used in German cars is no better/worse than glass used in US cars. Often it is the same, just made in European plants of the same companies.
4. The laminate comes from the same 4 suppliers for everyone and is the same grade. There are exceptions in China.
5. The major difference between brands is how well they fit (this is hard and takes know how), high quality black silkscreen, proper thickness spec, how well they are annealed on cool down, and how well the edges are finished. All have a huge effect on how easily the windshield fits and/or easily breaks.
6. Stay away from Chinese glass such as FYG, and the like, unless it comes from one of the above companies – not good. Safelite also makes its own and can range from mediocre to OK, depending on the car model. Most glass made in Mexico is made by one of the above or Vitro/VVP which is OK.
7. If you don’t ask, you will likely get Chinese glass with some installers, as it is cheaper for them and thus more profitable.
Hope this helps.