If I do leave android, I think I'll also miss the sky map, i also miss the core maps app. The android maps app blows the iOS one right out of the water. I think I'll miss the whole intergration with online services mostly and being able to tap and hold for more options or use a command with any program (lets say I want to search for a business. I can do a google search, yellow book or yelp. No need to go in each app, a pop up will ask me what program I want to use I tap the program and it opens, I can also set it as the defalut one too..
also a big one would be what Rene said, the voice intergration. Pretty nice, I can say my text message or say the website I want to visit, not just call home, or play party playlist.