First 4.3 update or second one? The first one was (not has, was) a bug. The second one is supposed to make the phone work again.

 

I have (sort of) experienced the unresponsive thing.

This morning, when I took the phone off the charger, the LED was blinking that I had email, but I could not turn on the screen or make the phone do anything. Couldn't even power down with the power button. Had to do a battery pull.

A friend with the S4 has been experiencing this regularly (and ultimately sent the phone in for a replacement) but this is the first time I've had that happen.

Comment which may or may not be of use: It has always been a little slow responding when I take it off the charger. I generally have to hit the power button a few times before it will accept it and turn the screen on. I assume this was related -- i.e., this time, the phone just failed to kick in.

Happening just once, I'm not concerned -- but if it starts happening regularly, action may be necessary.

 

I just did the update a few days ago. I haven't notice any issues with wifi, except Samsung Knox security waring box poping up when connecting to wifi for the first time. (Box hasn't poped up since yesterday.) My issue is slow responsiveness. Like it takes a second or two when switching thru applications. I've been playing around with Window Animation Scale; Transition Animation Scale and Animator Duration Scale under Developer Options. Its improved some, but things are not as smoothed like before the update. (I'm running a live wallpaper as well.) I'm going to tweak the settings some more and use a regular wallpaper and see if that makes a difference. I've had my phone freeze on me twice since the update, leading to a battery pull. (Not sure what caused it.)