Change time on one clock to automatically change the rest. Coordinate your meetings, catch up with friends and see if your mom is awake with Waqt.
I'd change this input, so that I don't have to change 'mode' from place to time and vice versa, application can distingush them itself. I don't think there is a city called 11:30AM or 16.00 :)
Very simple to use, clean interface, no hidden features
Necessity to change 'mode' from time to place