Faster for simultaneous tansfers, sftp or ftp over ssl

[goober]

Hi all,

I'm looking to speed up encrypted file transfers. I transfer a couple of gigabyers every few days
and am curious what is the faster transport, sftp or ftp over ssl?

My ftp server is vsftp ..which I've read is pretty fast under load and scales well also allowing me to chroot
user connections. But for simultaneous file transfers what is the better transport? Are there rule of thumbs
for how many simultaneous connections I should run versus overhead to manage connections? Rsync is
very fast but I'm assuming encrypting over ssh would make it similar in speed to sftp.

TIA, gp