I've been carrying around 2 phones for several months now, and it's been interesting to develop habits which clearly favor one over the other. Here are reasons why I'd go to my iPhone:
  1. The camera is better
    Images are much much higher quality, it's really fast to open for a quick photo, and the Photos gallery is much smoother to browse, share, etc.
  2. Nearly every social media app is better. Facebook, Instagram, Twitter, Snapchat, ...
    They seem faster to load, smoother to browse, faster to perform actions. To be fair the difference is usually small (maybe 10% better), but that's still enough.
  3. The notifications experience is better
    In particular going directly from the locked out screen into an app is better than the android experience where you have to unlock and then scroll through all notifs.
  4. The battery lasts longer
    This probably depends on the specific android phone I'm comparing it to, but I've been pleasantly surprised with how long the iPhone 6 lasts.
  5. Apps that aren't on Android yet
    e.g. List App