Cyberduck is a very complete open-source FTP and SFTP client. It can also be used to browse files on WebDAV servers, Google Docs, and Amazon S3. It has a very clean interface which emphasizes ease of access and speed. It works very well for FTP and SFTP connections and it has Growl support. It also uses the Bonjour protocol to detect servers in your home network.
I personally use Cyberduck a lot to SFTP using SSH into my iPhone and a couple of other networking devices. I never had the application crash at all, even while transferring massive amounts of data.
There are two connection modes: quick connection and the normal connection mode. For a quick connection, you only type in the address of the server and Cyberduck then asks you to type in any necessary login information. The connections manager is excellent to save all the connections that you generally use. After you connect to a device once, you can simply save the information to the manager, which will allow you to connect with a single click in the future. You can open as many different browsers as you want from the File menu.
Cyberduck is an excellent FTP and SFTP client. It has several advanced features that make it suitable for almost any uses. And it is also great for basic FTP connectivity.