Devart SecureBridge is excellent.
Gives you full SFTP client and server ability.
I used it to create a super cool managed SFTP/FTPS server with pattern matching rules for incoming files and it can then move the files to UNC locations, SFTP or FTP locations, email the file internally if it is small enough for email system etc.
Also has built in support for automatic PGP encryption and decryption (uses tprocess for that)
Also has built in ability to run a python script if no rules are defined in the SQLite database it uses as well as a built in magic byte checker with options for a file type whitelist and what to do if a incoming file is not in the magic byte whitelist.