I've read that Battery Minder products are high quality. They also have a desulfating mode which most Battery Tenders don't have.
I had intended to purchase a Battery Minder to get the desulfating feature but the Costco deal on the Battery Tender was too good to pass up as I walked past the display so that is what I have. Apparently the confirmation bias toward my purchase was so strong that I completely forgot about the Battery Minder until it was mentioned today.
I don't think that you can make a mistake with either.