Used before is way different than heard of. If I've used it before and liked it, sure I will favor that brand based on personal exp. If I didn't like it, of course I avoid it.

If I've only heard of it, that means absolutely nothing to me and I'm immediately skeptical. If someone has told me a brand is good, I'd consider it an informal review and it holds a small amount of weight.

Functionally, the brand is only useful for identifying and matching the products to the reviews and research I'd done on it, it's just a label.