The iPhone XS and XS Max seem to indeed be with the "most durable glass," at least when it comes to Apple's handsets. Several anecdotal drop tests against previous iPhones like the X have already showed they break harder, and consistently survive from bigger heights than before.
A machine drop test, however, is the only way to remove as much as possible of the too numerous variables that arise when hurtling phones to the ground, and the one you see above does exactly that. Here, the iPhone XS Max bodily endurance is compared to the Note 9 and its Gorilla Glass 5 wrappings.
We won't spoil all the fun, but will just note that the XS Max indeed shatters much harder than previous glass iPhones, though a consequent mishap with its touchscreen placed the Note 9 a photo finish ahead in the end. Harder-to-break is good-to-hear, as the back replacement can set you back a hefty sum, and yet we'd recommend putting this puppy in a case the second you open the box up.