Having recently started learning Elm, I am considering switching over to ReasonML. Elm's architecture is really great for front end development and the error messages are awesome, but the ecosystem is in its infancy, and development is driven by just one guy. I've seen a lot of open PRs and issues on Github with genuinely great features, but haven't been merged in yet.
ReasonML's documentation also seems better (especially for a functional programming newbie)
ReasonML's documentation also seems better (especially for a functional programming newbie)