[zalew]

> if you have a large site its cached for every other page visit

until you modify your own js (not that rare and uncommon) and it's back new and shiny again. from the cdn, it's just already there sitting in the browser's cache.

> Is it really that big of a perf hit

maybe not, but if you had the option to wake up with your teeth already brushed, wouldn't you take it? :D