Spends tons on crappy nilkin and ozly glass with the same no screen glue bs.(the sharp edged hurts my ear when calling too) And a few other generic non-full cover glass.(is it so goddamn hard to make?) Got feed up and torn it off one day. Been using without glass and case for a month now, no scratches on both screen and metal. Dropped a couple of times on ceramic and carpet, no damage. Went to the beach and got sand on it, still no damage. Wash it under tap after beach, still no water damage. Thought I fear one day it will all come back at me, so do not recommend you use it without protection.
Seriously, oneplus may design their phone however beautiful, but if any protection at all null the "curve screen glass technology" I'll rather they keep it on the board and make a more functional phone that need no protection like the htc.