Bought the back cover, and it's quite nice as you can still see the beauty of the phone through it, and it makes the phone much less slippery, albeit a bit sticky. Probably offers some protection against minor knocks too. I've only just put it on, but the main problem despite making sure the phone was scrupulously clean before application is that I have lots of bubbles. Not sure if these will totally disappear in a few days or not. We will see.
Less then two weeks later and nearly all the bubbles have gone, but the case is already starting to peel a little on the edges (see pic) Despite the thinness (probably less then 0.2mm) ,it is made up of two, possibly three layers, and its just the top one that's dissappearing. So, in conclusion a nice idea, but needs more refinement before I could recommend it im afraid.