Transmit is a paid app ($45/one-time fee with a 7-day free trial) that goes above and beyond what most file transfer apps can do.

What makes Transmit so special? Other than having a well-designed, easy-to-use GUI, it can work with more services than you've probably heard of. Transmit can interact with Amazon S3, Backblaze B2, Box, DeamObjects, Dropbox, Google Drive, Azure, OneDrive, OpenStack, RackSpace, and any server that accepts FTP, SFTP, or WebDAV protocols.

The one caveat to the list of servers is that Google Drive support will soon be phased out. If you already have a Transmit > Google Drive connection established, it should continue to work. However, once support for Google Drive is no longer an option, you will not be able to add an account for the service. That's pretty common with apps like this: when Google makes a change, support is often broken.

Other than the Google Drive issue, Transmit is an outstanding app for moving files. I've used it mostly for moving files back and forth between SFTP servers, and it does this to perfection. I can even connect with SFTP servers using SSH Key Authentication, which makes it more secure than using username/password credentials.