Ah, just minor stuff. The ones I can think of off the top of my head are an indicator in the status bar for power saving mode and you have to agree to use ultra power saving each time you use it. The big change for me was the radio.
Better connection while in areas with iffy signal and overall call quality.
The old radio sounded hollow and echoed a lot. Low volume too.
ANF3 fixed all that for me.
That's funny, I upgraded from a t959p sgs4g. I beat the hell out of it. It never gave up even with all of the overclocking I did with it.
I still have it as a spare or for when I go dirt biking.
Sent from my SM-G900W8