It's whether for you guys to believe this or not, your choice.
Well i have to say, iOS 6 improved my iPhone 4s's battery life. BUT NOT FOR LONG.
I've been reading most of the threads regarding about the battery life, as usual, setting the smartphone to becoming a really 'SMARTPHONE' by disabling most of the settings just to prolong the battery life.
So about believing or not believing, I've stopped charging my iPhone via charger included in the iPhone box. Because of the speed charge, it doesn't really give an accurate calibration for the battery IMO. As a result the battery drains really fast. I am now using to charge my iPhone via USB connected to my PC. Though it gives a relatively slow charge, but the life of the battery is much better.
Not to mention, I've restored the phone to factory settings for a number of times as iOS 6 isn't really impressive. Lots of bugs/errors to it.

It might not* be outstanding to some of you guys, but I'm quite happy with it now.
For the past one hour, I've been surfing safari to read blogs and being here in apple forum, Whatsapp and facebook. Pretty much that's about it for that current usage.