Is a quooker tap worth the cost?

Hi - we need a new tap in our kitchen sink and are considering installing a quooker tap to give instant boiling water. Do any gransnetters have one? What do you think? DH says it will be a pain because we live in a hard water area so will always be furring up. Do you agree? We have five grandchildren - are there any safety concerns? Does it actually dispense boiling water so that a pot of tea won’t be scummy? Would really like some thoughts from experienced users before we make what could be the best gadget ever or just an expensive mistake!