Hello! Both of these plugins look like they provide a good solution, and at least one of them looks like it should work with the latest version in WordPress 4.8, but neither one is “official.” There are discussions going on around menu endpoints but it is not a priority for the REST API team at this time; I’d suggest trying both those plugins out and then using the one that works for you. Since with e.g. WP-REST-API V2 Menus the route will be menus/v1/menus/..., even if WordPress Core does eventually support a menus endpoint it will not overwrite the one the plugin provides, so your application should continue to work without issue.