Have to disagree with some comments above. I got my first Quooker 14 years ago. Apart from 2 services and a replacement spout it functioned perfectly without fault and zero cost in all that time. New kitchen last month, new Quooker. The new ones are hotter than the old ones, the old one admittedly was fine for tea but did leave a very slight "froth" on the top suggesting it was scalding hot but not boiling. This is no longer an issue.
It is my "go to" appliance in the kitchen. Not just for hot drinks, but pans of hot water for boiling veg, for mop buckets, swilling the wheelie bin out or anything you would use a kettle for or boil from cold.
There is zero noise from my Quooker, zilch.
I had a Smart Meter fitted at the same time as my new kitchen and the resting electric charge, which is presumably for stand by items such as boiler thermostat, 2 freezers, 2 fridges, a mains connected clock etc as well as the Quooker is 4p an hour.
I would argue it's madness not to have one.
Not cheap though, my last Quooker was probably about £700, this one which is standalone without any of the fancy chilled water, fizzy water etc. was £1200.