Cyberduck is a free FTP client with a simple GUI that makes it very easy to handle your uploads and downloads.
The client handles FTP, SFP, Webdav and Amazon S3 transfers. Adding a new connection is very simple and only takes a couple of seconds. You can also drag and drop bookmarks to and from your Finder. The interface is easy to use and will probably be well suited to first time users. You'll also find that Cyberduck is compatible with most external editors like BBEdit, TextWrangler or TextMate.
One major complaint coming from Cyberduck users is that FTP login and transfers can be a little slow. Obviously this is a bit of a drawback, since transfer speed is one of the main benchmarks of FTP clients. However, many of the fixes introduced in the latest version compensate somewhat for this. The CPU hogging issue after completed downloads has been fixed as has the option to connect to services such as Dropbox.
Overall, Cyberduck is an efficient and elegant open source FTP client.
