Like quite a few others here, I place my iPhone head down. So placing the headphone jack at the bottom makes sense. However, where will they placed the volume button? I don't always use the apple issued earphone. So some of my earphone doesn't have the speaker & volume control. With the jack on top, I can easily press the vol button w/o having to pull out the phone from my pocket. That's the only issue I can think of when having the jack at the bottom. Not a big deal though.