I use a Nexus 4.
My one biggest gripe about using iOS mobile devices (pre iOS7) tied into one problem actually, the home button. I understand Apple is trying to be simplistic, but ONE button that does multiple functions is too much. I would often times hit the home button twice and BAM it would close the app I was in and take me back to the home screen when I wanted to kill an app. Then I would start trying to click two more times again and it would register as three clicks and turn the screen negative. I would set there for minutes just trying to get the app management bar open, and then I would accidentally have a slip of a finger (or sometimes i guess the screen just sucked at sensing the constant pressure of my finger) and it would open the app I wanted to close just sending me back into the endless cycle. Also with there being no back button, I would have to rely on the apps built in button or the websites, which would fail a lot because of the tiny screen, or just be too close to another on screen button and cause more actions I didn't want to happen. I guess this is why my favorite feature of my Nexus 4 (other than phenomenal battery life) is the separation and inclusion of a back, home and app management button.