Widget Importer & Exporter is a free WordPress plugin which enables import and export functionality for WordPress widgets and their data. The plugin is very useful for moving widgets from one WP site to another, you can easily backup them and theme developers can provide users with sample widgets.
UPDATE – Another new plugin WPS Menu Exporter is now available for exporting menus and it works with all latest WordPress versions.
You can easily export all your site menus for backup or for using them on another website of yours.
If you are looking for a plugin that exports ALL user data and meta data of your WordPress site to CSV then WordPress plugin repository has one good working plugin, using it you can get users data on spreadsheet. Even you can export the users by role and registration date range.