I thought initially that my battery life on my 4S wasnt great. After reading this thread I can see that mine is actually very good and the problems some of you are having are nothing like that I was experiencing.
So to add a bit of balance to the thread Id like to point out that mine is decent and I solved my removal of the 3G switch option buy just turning off cellular data instead.
The way I use my phone is: Connected to wifi in work and at home, no need for cellular data whatsoever. Then if Im not near a wifi connection I will switch on cellular data (for browsing, using Siri, or whatever) and then simply switch it back off when not needed. Thats how I used to use the 3G switch on the iPhone 4 as well.
The way I see it is leaving cellualar data on when not in use is like leaving your TV on when you are out of the house - a waste of power.