Hey OP, you are going to get a lot of 1d+ pics from several users. Pay attention to those users pics. Those screenshots will show that they use the S4 as a glorified iPod TOUCH.
If you have a weak 4G in your town, you will lose a hellish amount of battery life. also, if you make phone calls, you will lose a lot of battery. You used Pandora? That requires a signal to get the data. That will kill your battery.
If you go to non fanboy sites, even go to the official Sprint forums, it's pretty much confirmed what I had feared; the S4 has a weak cell radio in it.
Oh, one more trick, most of the 1d+ users, have the screen set to auto, or all the way down, have apps that kill most of the function, and they shut off most of the stuff when not used. Like, no syncing email, airplane mode when not online, etc.
This is coming from a very jaded Ex Samsung Fanboy, with a family of ex fanboys. Wife, kids, and best friend have had every Samsung Android phone out, plus the Instincts before them.
In other words, if you use your S4 like an iPod Touch, or a dumb phone, you will get a great battery life, with 4+ hours of screen time, if you use it as a phone or internet device, your battery will suck. It's better than the S3, and much better than the S2, but that's about it.
Wait for the fangs to come out and flame me, but just look at the screen shots.... The truth is there.