I was reading a post on David Tesar's extreme blog about FTPS. Good news is that we will be supporting FTPS in IIS7.0!!
People dont understand what the difference is between FTPS and SFTP are and in many cases the technologies are referred to interchangeably. Problem is that they arent the same!
FTPS is about using the same standard FTP protocol but tunneling it over SSL. So its really industry standards all the way. Great so isnt SFTP the same? Well no actually its not. SFTP is essentially using SSH as a file transport. In testing recently with a friend of mine we found it seemed to have big performance problems and issues with very large files (like 2GB+). So if youre planning on using it for a secure transport over the internet check the version of the SSH server youre using as there are some known issues. Otherwise try use FTPS with Windows Server 2008!
or if you have an unlimited budget, then use something like ConnectDirect from Stirling Commerce :)