I’ve never used a case for my iPhone(s) previously, but I picked up one of these a few weeks ago and I like it. I particularly like the way the plastic stops at the metal edge leaving the rounded glass edge fully exposed (so you get a nice smooth finger-on-rounded-glass feeling when using the back gesture). Granted this reduces protection, but I mainly wanted something to make the phone less slippery.
I went with white for my space gray phone, it is pretty translucent and barely lightens the gray color. (thanks Dave)