I love mine, It takes roughly one minute from pushing the button to a nice clear screen. But you still have to be cautious, because the screen may be clear, but your wipers can still be slightly frozen. So as you try to wipe the water away, you can end up ruining your wiper blades.
My KIA is the opposite as it has a heater for the windscreen wipers blades but not the screen itself.
Can’t imagine what the designers were thinking of when they designed that but luckily the cars heater produces heat to the screen very quickly for a diesel.
Mind you I was a bit worried last month when I turned on the wiper heater after a long Summer recess and smoked appeared from the dash as I thought something was on fire but no worries as it turned out to be just burning off the Summer dust that had collected on the heater.