For my part under Windows (which I used for a long time) and now under Linux I use the excellent FTP client Fillezilla a free world software.
It manages the following protocols: FTP, FTP over SSL / TLS (FTPS) and SSH file transfer protocol (SFTP)
Moreover it is totally free for those who can not afford to pay proprietary software;
Informations and download links can be found here:
https://filezilla-project.org/index.php