Not sure if its just me? but with my aqueon 60 gal tank the glass was was near impossible to scratch. I dropped rocks, ran sand over it with scraper magnets, razor blades in the wrong direction. Nothing scratched that tank glass.
Now with my Marineland 90 gal the glass just seems soft to me. If i am not extra careful to clean my magnet the tank gets scratched.
Anyone ever notice a difference between manufacturers and glass scratch resistance? Might be worth thinking about when picking a manufacturer.