I bought an OtterBox Commuter when I bought my Evo 4G two years ago. I figured if I'm going to spend $300 on a phone, what's another $35 for peace of mind? I eventually grew tired of the bottom flap on that case and stopped using it to access the battery. I broke that phone by throwing it at a wall last October and received an Evo 3D as a replacement. That phone seemed a lot sturdier to me, so I didn't bother getting a case.
This phone, however, is so thin that I just feel like I need a case. I ordered a black Commuter since I felt the Defender was too bulky and I didn't want a pink Commuter. After having my phone naked for about two weeks and covered for the last week, I love my OtterBox. Neither flap is as big as the one for the Evo 4G so this case just feels so much better overall. It doesn't add much girth, but it's fairly noticeable if you have smaller hands like I do. I figure I'll get used to the case with time. And since I don't have to worry about accessing the battery, I shouldn't have to worry about wanting to shed this case. I guess if I ever decide to pull out the SD card, I will have to remove the case, but I never pulled out the SD card from my last two Evos so I don't anticipate having to with this one.