First and foremost is Google’s Cloud. Granted you can leverage this on your iPhone, but you’ll never achieve the same level of seamlessness as you do on an Android.
Chrome is fast and the search history is mirrored across all of my devices without issue.
The home screen widgets have proven to be vastly useful, decreasing my time spent flipping open apps, especially when it comes to looking for or creating email.
Apps. They seem to install faster. Not a big deal, but anything to reduce “drag” is a plus in my book.
Google Voice is accurate, works, and doesn’t feel like I’m hammering down the button on an intercom. You should know what I’m talking about if you’ve used Siri.