I use and love Cyberduck, but if you're looking for a change you could consider Fugu (also free) or Transmit ($30).
These would be different from Cyberduck in that they use a side-by-side view of your local drive and the remote drive. I find Transmit to be a bit prettier, have more features, and to be more polished, but to each his own.
I used to use CyberDuck, but switched to Transmit when I got my MacBook. For some reason, some part of CyberDuck was being run under Rosetta; performance was horrid, especially with large files over SFTP. Transmit, has been nothing but rapid.
i use cyberduck when i need to ftp. got nothing else to compare it to since i used to use the sftp/ftp client via terminal -- which i still use for large transfers
CrushFTP4 for anything that requires heavy lifting.
Cyberduck for anything that does not. I'm not under the impression that you do not need more usability with your client, so I'd stick with it as a freebee.
I use Fetch mostly... but I'm trying out Transmit... i'm one for eye candy and Transmit looks pretty, i also like the side by side view of local and remote server. I wish Fetch would do that. But I still like Fetch a lot.
I have Transmit and YummyFTP, and kinda randomly switch between them for different tasks. I love the Transmit droplets, but for working with files remotely I use YummyFTP usually, just find it easier to navigate for some reason (plus the synchronized navigation works better, don't have to turn it on each time I log in).
I use Cyberduck because it's free and I'm actually starting to like it as I have gotten used to the interface but Transmit is simply the best. I downloaded the trial and loved it.