I've just binned my iPhone 5 for the Nexus 4 and can honestly say I am glad I did.
I've adapted to Android and the size of the device a lot quicker than I expected to.
Using it has showed my personally that iOS allowed me to just use the device for its intended purpose, and the iPhone 5 battery is much better. However, using Android on the Nexus 4 is just something else. The battery life on the Nexus 4 is not a problem for me. I can get 20 hours out of a charge with my usage. It is less than my iPhone, but still fit for my needs.
I wouldn't say I am a heavy user, but I do have Exchange Push, GMail Push, iCloud Pull, Bluetooth on, Juice Defender controls wifi, Mobile is always on, minimal screen brightness. I check email, Facebook, twitter and browse the Internet couple times an hour.