I have a few qualms with this app. I've easily and securely sent things from one computer to another using a simple FTP server, with all of the features that croc has listed. As for CLI support, I've written a small helper tool that allows me to transfer via CLI - giving me more security since I don't pull in any dependencies in my own code.
Isn't FTP still plaintext?
It can be or it can be encrypted. FTPS(i|e) implements encryption over FTP. I prefer SFTP as it just uses one port which I can define. SFTP also works better through firewalls and NATs.
VSFTPD is an example of an FTP server that supports encryption or FTPS.