My wife uses her iP4s for work, constantly on calls and sending texts and emails. She carries a charger around with her at all times because its usually just about dead. This is after over a year of constant daily use, so I'm not surprised the battery is dying.
My S4 does well with screen brightness on auto, WiFi disabled (don't need it in my area, strong 4G coverage) and GPS disabled most of the time. 4-5 email accounts, I do not have FB installed as an app (the silent battery killer, IMO) instead I go thru Dolphin Browser if I want to look on FB.
I am generally at 50-60% by the end of the work day with moderate to heavy use. I carry a spare battery with me, it makes it nice on those days where I won't be going home right away and I can just swap batteries and keep going.
The S4 battery performance definitely stacks up very well compared to any other smart phones out there. I'm sure its not the best, with the size of its screen, but it definitely is not the worst. My SGS1 and SGS2 were much harder on batteries than this one has been.