I had the z3 compact before the z5 premium and loved the phone, but destroyed it 5 times within the 2 year contract.
When I upgraded my phone I decided to do the sensible thing and get a decent case for it, and this case has been outstanding!
Yes, it is a bit big, and yes, its a bit heavy, but what do you expect from a phone case that has rubber, gorilla glass and 2 sheets of metal screwed together!
It has lasted me 18 months and has surprised me every time i pick it up off the floor and hasn't broken, so much so I ordered another case yesterday as mines a bit scratched up after the abuse i've put it through, but inside, an immaculate, as new phone.
Couldn't recommend highly enough!