I am going to list the common issues with my i9500.
Got it 2 weeks back and have been testing it thoroughly. Currently on latest ME1 firmware.
2b. New crash issue: open camera, go to settings, press the mic (sound) button and the camera crashes.
3.Phone turns off all by itself.
(Hapenned twice in two weeks)
4.When the phone is turned on again, the battery levels jumps down to 10-15 percent less of what it was before. It is also displayed in the settings battery status graph.
5.When the volume is set to max during a call through earpiece, the slight vibration made because of the sound emission is felt on the back of the device (in a cheap way) every s4 has this issue.
6.Launcher redraw (Even after updated ME1 firmware but its improved and only seen when doing heavy muktitasking)
7. Screen smearing issue.
8. Slight pinkinsh/purple tone on the lower right half of the screen when the brightness is set to lowest.
9. Flash light less bright than other phones eg nexus or s3
10. Camera Lag when opening
10a. Shutter lag when taking photos
11. Gallery lag when opening
12. Dialer lag
13. Contact app lag
14. When the keyboard is popped out on say a white web page, the screen does a slight brightness adjustment that it almost feels like a screen flicker on low brightness. Then it changes colour tone from reddish to greenish.
15. Notification bar ocassionally stutters when pulled down or pushed back up.
Whoever gets any of these issues please keep confirming or adding any more issues I missed. All these issues are currently present in alot of brand new s4 units worldwide.