I just got my 4s a week ago. My Droid (or Drone) was horrible on battery life. I had a monster battery on it and only then did it seem normal. I was using a lot of power the first few days with the new phone, but then I was downloading a lot of aps. I took my iPhone off the charger 16 hours ago and it's sitting at 64%. I did do some things with it, but nothing earth shattering. My wifi and Siri have been on all this time and I've been receiving emails. Like some of you, I'm currently working on battery life fine tuning.
When I ws shopping for a replacement phone I discovered the 4g phones chew up a lot more juice and after having gone thru 3 batterys with my original Droid, I said no thanks!!! If the new phone is faster and does more then I imaging it can easily use more, though Apple is claimimg there's a better battery in the 4s. I hope to avoid getting one of those add-a-battery-wrap-around cases.....