Battery Life Is A Difficult Issue
Similarly with my iPhone 4S, I found that the battery was easily able to get me through a full day away from charge - despite many others complaining of extremely poor battery life.
Why is this the case? I have no idea. My Wi-Fi and Bluetooth radios are always enabled, I use Push for everything available and I use automatic brightness to manage the screen. If anything I'd expect worse than average battery performance.
Perhaps its the rigorous three charge/discharge cycles I perform when I receive a new phone. Whatever the case I'm happy for it to continue into the future...