Readers know I am an an oyster fan, but of Northeastern North American oysters, mainly Wellfleets but Blue Points are ok too.
Call me an oyster snob if you want, but I know what I like.
All East Coast US oysters are the same species, from Nova Scotia to Texas. Crassostrea virginica.
If you really want to get snobby about it, it's terroir. Cold water, winter hibernation, slow growth, briny water. I do not enjoy the same species from the Southern US, even if lightly broiled on coals with hot sauce.
OK, well we took a little lunch break on our drive along the mountains from Dubrovnik to Split and stopped in Ston for its famed oysters:

They might look ok, but like all oysters I've had in Europe they are not. Too salty, too flavorless, less zippy. Farm-raised, like ours. But ti turns out that those European coastal and Med oysters are a different species: Ostrea edulis. Don't bother.