I understand that UNC, SFTP, and SSH are, of course, different interfaces (protocols?). But feature-wise, how do they differ? Are there things you can do with one that you cannot do with another? Is one more secure than another?

The situation I want to fix is one where we have several Windows servers and VPC's, some of which have SFTP servers and some of which don't. For those that don't we use UNC over a VPN shared by the entire enterprise. What I want to do is either use all UNC, all SFTP, or all SSH (unless a real need to vary on a case-by-case basis presents itself).

Links would be excellent. My biggest problem here is that my googling brings up irrelevant results. :(