Updated to KitKat on Koodo Mobile here in Quebec
I have auto update turned off and I just happened to check a few hours ago, and there it was, ready to download and update.
I did the update and rebooted...so I see some very minor differences in the settings here and there, nothing much in the UI, except the battery indicator icon is now white instead of green...and maybe the OS is a tiny bit snappier. All my apps work - no issue there. I had Google Maps crashing once in a while when I'd undock - so we'll see if that issue is resolved.
I will see how battery life is over the next few days - but I can see much faster connection speeds to WiFi and far more consistent too. I used to connect at 108-135 on my D-Links WAPS, the odd time 150. Now it's stuck at 150 no matter what. I don't know if throughput is better or not, but I guess I'll see over time.
If I have any major issues, I'm gonna do a factory reset - but for now, it seems fairly smooth and stable.
EDIT: The OS has started to settle in - that said, I think battery will be way better than Jelly Bean was, and I thought that was great! The OS is getting faster and faster. I am able to use App Opps to change permissions wherever I need to. Pictures on SD card is no problem - I don't see what the issues are that people are complaining about with regards to this issue.