There's no one answer to that question. I'd usually pipe to sendmail for sending mail, seeing how there is a de facto standard for what commandline parameters the binary takes regardless of *nix as well as MTA flavour. With FTP clients, things are murkier. You can't rely nearly as much on it. There's also a different caveat with mail: your sendmail runs a queue, so if the destination SMTP is unreachable the mail will likely still eventually be delivered.

So, the answer is it depends. There's myriad individual considerations depending on what it is you're trying to do.

Makeshifts last the longest.