EDIT: though, one difference is this supports server-side rendering out of the box, while Mithril requires a (tiny) third-party module: https://www.npmjs.com/package/mithril-node-render
Definitely worth looking into if you're looking for a full stack solution.
EDIT: though, one difference is this supports server-side rendering out of the box, while Mithril requires a (tiny) third-party module: https://www.npmjs.com/package/mithril-node-render