Sub Zero fridges are terrible. The people I’ve known that had them rued the day they bought them.
They are a status symbols, that’s why they cost so much, not because they are top quality.
They are a status symbols, that’s why they cost so much, not because they are top quality.
It also is designed such that you absolutely cannot clean the inner layers of the fan-cooled condenser coil without major disassembly of the fridge. The service panel on the front can be removed, but there is a metal fan shroud that is difficult to remove and turns what ought to be routine maintenance into an ordeal involving taking things apart and taking the built in fridge out of the wall. Whether this was deliberate or just an oversight, I don't know. There would have been many other simple and cost-neutral ways to implement this cover.
My guess is your friends aren’t maintaining them properly (they know they have to clean the condenser coils every couple months, right?) Either that, or they have those “integrated” models with no visible vent for the condenser, which of course will overheat the compressors and electronics.