I use WinSCP. I cannot say much about technical differences, but it has worked well for me.
Also, PuTTY comes with a SFTP/SCP client, and unless there are strong reasons you cannot use SFTP, it is a lot better than FTP, security-wise (does not transmit passwords in plain text and allows using cryptographic keys rather than passwords; in fact, on OpenSSH you can configure the server to deny password authentication completely; and the entire connection is encrypted, of course).
It's funny I already use WinSCP but for SSH and SFTP connexions to Linux servers, it didn't even occurs to me that I could use it for regular FTP too. Thanks.
Also, PuTTY comes with a SFTP/SCP client, and unless there are strong reasons you cannot use SFTP, it is a lot better than FTP, security-wise (does not transmit passwords in plain text and allows using cryptographic keys rather than passwords; in fact, on OpenSSH you can configure the server to deny password authentication completely; and the entire connection is encrypted, of course).