Probably because it has an attractive UI that makes it a little more approachable (subjectively) for web developers than the likes of Textmate.
It's not as if Transmit really brings that much to the FTP world, but people seem to really love it.
It's not as if Transmit really brings that much to the FTP world, but people seem to really love it.
I've also found that FTP clients on Mac are missing a nice feature found on many Windows clients: multi-part (accelerated) transfers.