I have some clients that were asking about recursive ftp so they could
download their websites. They have only ftp access to the sites

They have access to a PC running Linux, and are now using ncftp

ncftpget -R -v -u <username> -p <password> <domain.tld> <path to local directory>  <path to remote directory>

remote directory might be /web
note if you have subdomains using '/' won't get the vsites.
you must explicitly use /vsites

Hope this helps someone.