I took the plunge and went with the Belkin Shield Micra, which arrived today.
It's a pretty basic and fairly cheap feeling, all-in-one, hard plastic casing. It's pretty thin and feels fairly brittle - a hard knock would probably break the plastic.
I wouldn't have paid full price for it.
However, it does protect the back and sides from scratches and the 'deathgrip' (I assume, as it wasn't occuring beforehand for me either). It also allows access to all the slots, buttons and lenses and 'slides' easily into your pocket.
It's also very understated (completely clear apart from small etched logo) - which is what I wanted.