The Nexus 6 has smaller bezel on the top and bottom than the iPhone 6+ which has to make space for the TouchID/Home button. Android uses on-screen soft buttons.
My biggest peeve with the onscreen buttons (using flagship Galaxy Nexus) is accidentally pressing them, primarily when I'm trying to take a selfie with the rear camera. It's insanely frustrating the way the orientation moves them around and trying to find the on-screen shutter button rather than clicking the home button.
