I using Orzly® Series Fusion Bumper Case for Xperia Z5 Premium. Love it. hard case at the back, not so soft but flexible on the side. Still fit nicely even use glass for front and back.

Features :-
- Polycarbonate and Toughened Polyurethane Hybrid Material
- Shockproof Absorption Air Cushion Design
- Quintessential Lift design of 1.0mm from Surface
- Lay On Table Lip Design
- 4 Points Ridged Rear Defenders

So far survive after a few times knock on the table.

Cons, only 1..  back easily get scratched.