Bulging camera -> broken glass. For two years I've been using a Galaxy S5 with bulging camera and twice I have broken the camera glass needing replacing, it's the first thing to hit the surface when i rest the phone on a table and takes a lot of stress. Of course I could be more careful. It has also scratched and so there's more lens flare, but I'm tired of replacing it. My wife's iPhone with flush camera is much less of a problem.
Anecdotally, my Nexus 5x has a large, central bulge for it's camera and the sapphire glass doesn't even have any scratches on it after almost a year with no protector over any part of the phone.
It's a shame they're discontinuing the line, the build quality of this phone is immensely good, it shows me the quality Android phones _should_ have.
I hate the camera bulge, but I've had an iPhone 6 since they first day they were available, and the camera lens is still in pristine shape with no case, and no particularly special care.
