It's quite frustrating, just to pick one, to figure out where to go when you want to change your wallpaper. Settings -> Display -> Wallpaper. Weird - maybe it's just me but "Display" is not associated with "Wallpaper" in my head. "Display" means things like screen resolution, which device I want the display beamed to, etc. Android is riddled with "not quite wrong but takes a second to remember" things like this.
I told my wife yesterday, "I didn't think it was possible that someone, in 2013, would develop a phone that was worse at event notifications than the iPhone but they've done it with Android!"
For reference, I've only been on Android for about six weeks at this point. I did two weeks with the HTC One, returned that (camera was not to my liking), and went w/ the S4. I like the display size on the S4. I imagine that, if nothing else changes, in two years I will switch back to an iPhone provided that the screen size is the same or bigger.
To me, iOS is better. I miss it.