I'm having data connection issues. I normally don't have my phone data enable on and I'm not able to get a connection this week. It was working last week so my APN setting is correct. My daughter is having the same issue. We're in Calgary
I'm in the same boat: I use Power Toggles to flip between wifi and mobile data (AutomateIt didn't work well for me) and I found that after a while (a week maybe?) mobile data stops working. I don't even get the icon in the upper bar.
Only solution (as you discovered) is to reset the phone (power-cycle).
Note3 on KK 4.4.2 here.