As a Verizon rep, I can tell you a bunch of people broke them within weeks of ownership. People came in with beat up looking S3, S4, S5 phones not in a case and left the store with no case. We recommended it, they figured we are just trying to be greedy and make commission.
Needless to say a few people dropped and broke them on day one. Had a few people come yell at us for selling them a fragile phone, and a few who wanted to exchange it but we couldn't because they cracked the back. One guy got an S6 Edge and didn't want to invest in a case because he wasn't sure if he would like the curved screen, was back 3 days later wanting to exchange for the regular S6 but the back of his phone was cracked.
Our Note 7 display was broken the first month it was on display, it got dropped on the counter, fell like 2ft lol. Coworkers S6 Edge plus broke while in one of Samsungs slim cases falling from a conference table to a carpeted floor. These are the most fragile phones ever and now Lg, HTC, Motorola, and even Apple are making glass backs.