Wanted to try the plugin out and get the following error on plugin activation.
Fatal error: Cannot declare class DrewM\MailChimp\MailChimp, because the name is already in use in /path/to/public_html/wp-content/plugins/rsvpmaker/mailchimp-api-master/src/MailChimp.php on line 13
Looking forward to trying it once this error is resolved.