I mix both: mainly using camelCase, but using underscores sometimes instead of conjunctions to make things more readable (as you say), especially to make some i

I mix both: mainly using camelCase, but using underscores sometimes instead of conjunctions to make things more readable (as you say), especially to make some important meta information stand out (as in "doSomething_locked()" for a method, to indicate that it must be called within some contextual lock). If using mainly underscores, I don't see what other separator I could use as a higher level separation. Maybe two underscores, but that could too easily be seen as a typo.