I've never broken a phone case in the fifteen years I've had a phone. However, it's not every day that you drop your phone over an ancient stretch of basalt cliffs. I thought I lost my phone in a deep crevice, so I was once I had fished it out, I was perfectly happy to see the phone was intact and that the case has done it's job.
The outer layer of the case cracked and continued to crumble away (while the softer inner layer still kept the phone protected) before I could replace it.
All in all, I'd say I'm pretty happy with it. It did it's job! I owned it for 5 months and plenty of your average every day drops or bumps prior to dropping it on a jagged cliff face.