Cyberduck is an open source SFTP (SSH Secure File Transfer) and FTP browser licenced under the GPL. It has been built from the ground up with usability in mind, having the same consistent graphical user interface for both SFTP and FTP browsing. Multiple connections are supported. Drag and drop is supported consequently for transferring files between server and client. A transfer queue keeps track of the pending file transfers and supports resuming of both downloads and uploads. Local files can be synchronized with files on the server. System technologies such as the Keychain, Rendezvous and AppleScript are supported. Cyberduck integrates seamlessly with external editors such as SubEthaEdit, BBEdit, TextMate and others.
Pros: Cyberduck handles both FTP and SFTP connections and contains many useful features (all listed in the above summary).
Cons: There are still a few bugs to iron out, but none of them are mission-critical.