The Bingsale ultra slim in my opinion is the best protective case for the Nexus 5. The sheath is fit and can freely recesses for the on / off switch and volume buttons, which is very useful in my opinion. The problem is often that other cases these two keys are overlaid with the envelope and are thus no longer optimal to use.
Furthermore, the material of the protective cover must be emphasized. It is wonderful rough, leaves no footprints and also still looks classy.
The only downside: Removing the shell is often quite heavy and you're afraid to inflict the Nexus scratches.