I feel like I'm actually of two minds on a lot of these options.
I like the idea of Sara being a corrupted servant more than I like her overthrowing her Master, but at the same time, I'm not really as interested in John winning in the end, as contradictory as that might seem.
The Sauron analogy from earlier kind of makes sense to me. Sauron sort of replaced Morgoth as Dark Lord, but he didn't overthrow him himself, he essentially inherited the role.
I'm also not someone who dislikes happy endings, but it wasn't my first choice in this case. I eventually voted stalemate. I think if it were up to me to choose something, I might pick "John loses, Sara goes back to being a kind waitress, but is still somehow partially corrupted."