I found the whole thread far more interesting when I thought the brands being discussed were slave symbols.

I think both opinions have merit. I'd certainly use period and 'dated' brands for a historical piece, and the most ubiquitous brands I could imagine for 'future-tense' stories.

I imagine any story set in modern times could use a mix of either, but I'd stay away from very localized brands... because one of Douglas Adams "faults" was being a bit too colloquial in my opinion. I always found him hard to read.