By let it down - do you mean they don't work very well? - or don't look very good?I'm editing our video review of the car, having had it for the week. It is a blast, and the rear drum brakes are the only thing that let it down.
All the MEB platform cars have a rear drum! - I would imaging this rear brake is effectively maintenance free as the main reason to change BEV brakes will be due to corrosion and the drum obviously limits this vs an open caliper, though it is strange seeing Audi Q4 ETron's with huge wheels and drum brakes!