Bottom. Honestly at first I was confused by the idea of the bottom but when people pointed out some things it makes total sense.
For one I do have a tendency to try to put my phone in my pocket top down, this means I still can do so. It also means the home button is easier reached if I want to take my phone out and look at it (plus the orientation of the phone is such so that I can read it vs. having to turn it around after taking it out of my pocket).
Secondly, all cords will be coming from one end so if for some reason you want the headphones and you are charging it or connected for whatever reason you don't have to worry about a cord coming from each end.
Practicality wise it just makes a lot more sense even if because of convention (from walkmans and on) it seems the top should be where the headphone jack is.
Though in the end it's not a huge concern to me either way, it just makes more sense to be on the bottom but in the end I'm mostly indifferent.
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I find the headphone jack at the top convenient enough, but as the phone is usually in my pocket when I'm using the headphones, it doesn't really matter.
My biggest design beef is with the camera lens location. It should be moved to the opposite edge, near the volume buttons. This would make photography more natural, and reduce the chances of the thumb straying into the pic.
I'm glad I'm not the only one who has this issue. I've found the fix for now is to get used to using the volume button as shutter (I am so used to using the screen and I don't use the camera too much so I keep forgetting I can use the volume button now) cause the way I hold it that way makes it easier to keep my fingers out of the way.
But yeah, I'd prefer the lens to be in the middle top, honestly, or somewhere not on an edge where my finger might get in the way when I'm gripping it.