When I picked it was between Ironwolf Pros and Exos drives.
From what I could find, both are identical but the Exos are better built yet also cost less? I checked the mtbf and everything at the time and some things were better on the Exos while still being lower priced, but I'm not sure if thats the same now.
IMO the difference in pricing was simply because ironwolfs are gamer brand, while exos are office / enterprise brand, and as such were even cheaper still when bought from an office supply store.
I just tried checking again, only difference seems to be that all exos drives are helium filled, while only some ironwolf pros are.
Regarding pricing, 16 Tb Ironwolf Pro £350, 18 Tb Exos £299.
Gamer brand vs Office brand is all I see going on there.