happy to provide links to good info on the Sixers.
I thought Pompey and Murph Man's articles about Simmons and Butler were interesting. Each broke down the respective situations from multiple angles.
That said, I do think in a lot of ways, the situation does boil down to whether the two players can be their best playing together. I think they can, though that's dependent on either Ben developing a jump shot, or giving up the PG role.
Horford is tempting, but I'd be surprised if he signed with the Sixers. I suspect he's going to want a max contract, and other teams are likely to be able to offer him more, and also have a more prominent role for him. With the Sixers, he'd either be a backup at the 5, or splitting time at the 4 (assuming the Sixers can re-sign Harris). The Mavericks or the Clippers seem to be the most likely landing spots for him.
Horford is 33. He wants a 4 year deal at ~$28 million a year. Hard pass.