That is cool to see, I know my 4S has WAY better battery life than the GS2 I had for work did, now I just have a black and a white iPhone 4S (work and personal).
But I know my iPhone 4 lasted longer throughout the day than my 4S does.
When I first got the 4s the battery was not as good as my 4 either but I ended up getting a replacement a couple months ago because of battery issues and the new 4s last just as long as the 4 did. With light usage I can make it 2 days again like I could with the 4.