I always see brand names on the back as a plus, and I have never had a customer react differently. Most don't care, but some react positively when I point out that I have used brand/series X or Y for this or that purpose.
Funny thing is, I use Oracal for pretty much all cut graphics, but last time I ordered some 3M wrapping vinyl, I got them to send a couple of rolls of 3M premask/application tape since I was almost out of Oracal premask and they had a shipment ready anyway. This has 3M logos all over it, and I've had customers light up when they read 3M, because that is the only brand they actually have heard of before. But if the 3M premask makes them believe that they are getting a better product, fine by me. The Oracal cast vinyl I use is excellent anyway.