Let me start by saying I LOVE Otterbox cases. I have had one on every phone I've had for the last 5 years. No compromise. I love not having to worry about anything. When I got my S5, I just felt like adding and Otterbox would make it too bulky so I opted not to....
At first I was using a basic snap on case... unfortunately, it only covered the sides and left the top, bottom and face all unprotected. Well, gotta love murphy's law... Someone was holding my phone, dropped it and nicked all of the unprotected edges. I was quite unhappy.
Obviously the next day I went out and got my Otterbox and don't worry about anything anymore. It was kind of bulky at first, but after using it for a day or two, I don't even notice. Plus, it's hot pink! (=