I just started copying some files from a Windows XP Pro VMWare VM to a Redhat 3.1 Server VM hosted on their own private network on a VMWare ESXi 4.x server.
Using WinSCP from the XP Pro Client with SSH as the transfer protocol I was seeing ~5,000KB/s. So I stopped the transfer and selected FTP as the transfer protocol and restarted the file transfer. The result: A transfer rate of ~20,000KB/s.
The point is, if you are not worried about someone sniffing your password and you would like a performance boost, falling back to a non-secure protocol can furnish you with significant file transfer performance gains.