FTP software is not the most glamorous category, yet CyberDuck for Mac manages to make file transfer appealing. With an attractive interface and support for cloud storage, it's head and shoulders above its competitors - and it's free.
CyberDuck for Mac is available for Mac and Windows and offers a number of features above its peers. It's an FTP and SFTP application, but it also supports WebDAV, providing easy access to web-based disks. It also connects to Amazon S3 for really affordable storage in the cloud, as well as Rackspace Cloud, Oracle Cloud Storage and Google Cloud Storage.
CyberDuck for Mac integrates seamlessly with other providers using two APIs: Amazon S3 and OpenStack Swift.