I don't particularly like either one of them, but I'm going to go with Sword in the Stone. Both feel pretty boring, but in general I like the characterizations in Sword in the Stone more, aside from Merlin who's just bonkers for no reason. The characterization and writing in Robin Hood is just weak in general imo. Sword in the Stone's biggest mistake is that it's climax has nothing to do with the protagonist, and the fact that this somehow eluded the notice of the people working on it speaks to how nonchalant it's ending is. I can't even remember the ending of Robin Hood, and I saw them both at the same time. Nothing in that movie grabbed me in any way.