I have the case mate pop and its just a tad smaller than my wifes Iphone 4 Otterbox Defender. Otterbox puts it at 16.77 mm thick. From the pictures it looks like the tough case is also a bit thinner than the pop because its form fitting. The cate mate pop is not form fitting, the back is completely flat. The Otterbox commuter is 14.80 mm thick so i'm guessing my case mate pop will be thicker.
i'm looking forward to the commuter because it protects the front a bit. So when it falls it will luckily strike that first and the raised sides. Its a given that otterboxs are lint magnet, i'm surprised because my caste mate is not. The shiny back does however drive me nuts, ITS UGLY!