Actually, I do care . . . if the brand reveals something interesting about the character, or if the generic alternative would sound weird.
If everyone in the room is wearing Armani suits, and the narrator — who’s come to pitch them on his idea for a new product — is suddenly very aware of his off-the-rack number from Men’s Wearhouse, that doesn’t feel like clutter to me. If the person getting into that dark blue Toyota Prius is a crime boss who’s spent the previous scene scaring the living crap out of two minions by quietly telling them that they’ve “disappointed” him, that’s (in the right context) a deft bit of characterization.
Realism is (even) more a case of “your mileage may vary,” but . . . when was the last time you heard somebody in a bar order “a beer” or “a lemon-lime soda” as opposed to “a Bud” or “a 7-Up?” Now, whether there’s any remotely compelling dramatic reason to include the dialogue (rather than just say “Susan ordered a diet soda; I had a beer”) is a whole other question. But if you’re going to do it . . .