I would like to get an Otterbox case for my Incredible case, but I don't know if I should get the commuter or defender. I need it to stay somewhat slim, because it is in my pocket a lot, and I need it to have some resistance to water and sand, because I go to the beach a lot. I can't tell which one is better. It seems the commuter is slimmer but the defender is more for resistance to water and dust. which should I chose?