I guess Luke wants us to create new options, not vote on the existing ones.

This said, here are my feelings from looking at the pictures:

• #2 and #3 are "someone is playing with the font trying to impress me", which repels me for similar reasons articles using many font colors repel me; it feels desperate
• #1 feels like an elementary-school textbook
• #4 feels like a novel

So I think #1 would be great for a gentle introduction into the topic of artificial intelligence for lay audience; and #4 would be great for a book like GEB. But I guess the prepared ebook is neither.