So my Otterbox case(Defender) has been working out ok, but it lets a lot of dust and sand in. I am planning to pick up the S5 when it's available, and I can only hope a waterproof case will come out quickly for the S5. But until the S5 is out, I am going to get a new waterproof case for my S4..... so who is using what? PEPK, Otterbox preserve, or life proof? Which do you prefer and why?