To connect to FTP servers and I have always used Transmit CaptainFTP. They were the ones I say convinced.
But if you do not need too many options for connection types and etc, you might come in handy OneButton FTP.
The interface is simple and very useful. We just asked the server, the username and password. We can connect and download files.
To upload just have to drag files from Finder into the window.
Download OneButton FTP