Fav cooktop + Any major reasons to keep same manufacturer for kitchen appliances?

[dogmom]

I have a Miele electric cooktop that is 21 years old with a Braun telescopic downdraft that still works great. I would not hesitate to get another Miele, although now I would go for induction. Also, all our appliances are different manufacturer except I have a Bosch oven and dishwasher. I’ve had to replace everything in the past 21 years except the cooktop and downdraft.