I too made the switch for similar reasons: iOS was getting old and unimaginative on a phone (but still have my iPad 3, for which the iOSis fine.) The transition hasn't been smooth.
1. I would have liked to have a lot of my music on the phone, but since I only have about 11GB free on the phone (in comparison, I had about 25GB of music on my 3GS), I have to get used to streaming via Google Play Music. Most of the time this is fine, but when indoors or on the road, the streaming may not be perfect, the music stutters.
2. Syncing contacts has been a nightmare. I have about 200+ contacts on Google and about as much on OSX/iOS. A lot of them are duplicates, with Google having emails associated with the names, whereas the OSX/iOS has phone numbers. I have yet to figure out how to cleanly and efficiently sync these two groups.
3. iBooks was a far superior book reader than whatever is on Android. First, Google's stock reader won't open epub files or allow to sideload files. You need a separate app for it. I have Aldiko, nook and kindle - all of these have their deficiencies and are less refined than iBook (and its store.) While Aldiko allows for sideloading and works with epub, there is no web or iOS equivalent app that would keep up with your reading, and its interface feels cartoonish. Nook works with epub and allows for sideloading, but your local files are not uploaded to their servers, so you can't continue your reading either on the web or on iPad (though you could do this for the purchased books). Kindle won't work with epub. iBooks had a powerful and elegant app, I was able to easily read between my iPhone and iPad, though there still isn't a web app for it.
4. There is no equivalent of iTunes University. I know of (and use) the android app Tunesviwer - but it won't afford you the control and access you get with iOS.
With all that, I still love Android and have not regretted the change.