I miss the physical home button and don't really like the back button.
I think this will change for you.
I had to use an iPhone recently for the first time (loaned from a mate while my Android was getting repaired) and the single most frustrating thing for me was the lack of a back button. I didn't have a clue how to get between various screens in apps, and each one seemed to manage it slightly differently.
Not that Android apps are 100% consistent with how they manage the back button, mind. It's much better these days but in the early days the back button was confusing sometimes.
Now it's mostly:
back one -> Take you back a screen
back twice -> take you to the top menu of the current app
back three times -> take you to the last opened app, or to homescreen if you didn't come from an app
One nice thing Android does is allow apps to share stuff between themselves. It's on iOS now, but I reckon Android does it better as it's been baked in since day 1.
Hit the share button in an app and you'll see which apps are configured to receive data from that app. The "clipboard" is usually one of those, and I find that handy.
But for things like sharing a dropbox link with a friend on WhatsApp:
Open dropbox and go to your file/folder -> hit share -> choose WhatsApp -> pick your friend.
As you can imagine, there's lots of different combinations of shares depending on the apps and they all seem to Just Work.
Facetime doesn't really have a decent alternative on Android. There's skype (meh), WhatsApp itself (still a bit meh), or Hangouts - which is actually really good, but no one uses it.