To be honest I rarely use it, I usually have the clutch down at traffic lights. Only time I really use it in traffic stockings when I have to wait for a while.

You let go of the clutch and put the gear in neutral and the engine turns off, when you touch the clutch the engine starts up instantly, it react extremly fast.
It works good but its not something I have been missing my whole life

No it doesnt work right away and not when its less than 4 degrees Celsious outside. Here , there can be improvements I guess.