I took my 4S to a local Apple Store to get its battery issue fixed.
They hooked it up to their diagnostics, and told me that there are multiple crashes in essential OS features of the phone that are causing the issue, but the battery is normal. I told them that I have tried everything already. I restored the phone to a new state, installed IOS 5.1.1 on it, and only put in essential apps that I needed.
At that point, for some strange reason, the apple respresentative decided to offer a "battery replacement" to me. This was weird because a few minutes back they told me that the diagnostics had revealed the battery was normal. Nevertheless, I gave them my phone. About 15 minutes later the apple rep came back and said that the battery replacement went bad, and they will give me a new phone out of the box!
Not feeling too good about this, I went ahead with getting a new phone. Installed IOS 5.1.1 on it. I then decided to stick around the store for about 30 minutes to see if the same battery issue persisted. After 30 minutes and making one 5 minute phone call, my battery went down from 70% to 60%. Mind you, this is a new phone that apple just gave me and with the latest OS installed.
Then finally I got some truth from Apple. The Apple rep told me that the 4S battery life is not as good as the 4. Its processor is bigger and eats up battery even when the phone is idle. Disabling software features like location services, and time zone checker, just puts a band aid on this issue, but I can never expect to have same battery performance as a 4.
At that point they offered to give me an 8gb Iphone 4 with a $100 rebate. I am at home now, and still considering that offer.