There is a difference in the marine stuff vs automobile. Doubt there is significant difference between brands.
Anecdotally, a guy I knew who has a "Master" marine technician who's family owned a Mercury dealership and a marina grew literally up in the shop told me he always looked at the oil containers in the boat when they came in for work and never saw a blown motor with the marine Quicksilver, Yamalube, or whatever marine oil there were always automotive oil containers.
Walmart sells the Merc stuff and for as little as the small outboards use I've gone with the marine stuff.