This KK update is fast and smooth, and has a much better RAM management than JB, but it has bugs as well and I hope that Samsung will correct them in the next versions.
Usually the first ROM they release is a bit buggy, then people test it and eventually comes a better version with bugs fixes.
Feel free to add your KK experiences, complaints etc. here.
for me the main bug, and it's actually a deal breaker that made me downgrade back to jb 4.2.2, is that when an app forces close the phone reboots.
Pretty annoying to say the least, moreover that some apps being not compatible with KK they force close and make my Mega reboot, you can imagine the mess reinstalling all my apps after the upgrade.
Clipboard saver, FC, reboot!
AOSP browser, FC, reboot!
Maverick, FC, reboot!
And so on, and so on, that's not nice...
I've tried everything with no luck.
I even flashed the ROM again, did a factory reset and didn't root in case the problem came from there but nope, FC still leads to reboot.
Hopefully Samsung will do something about it, but until that day comes (if it comes) I'm back to JB 4.2.2.