I have recently came across the FTP Rush and I have to say I love it. It is very fast and seems to be rock solid, especially when processing massive queues of several million files.
One question though - can it compare files based not only on size, but timestamp as well? The "file exists" dialog only seems to mention 3 options "files is larger", "file is the same" and "file is smaller". I assume in all 3 cases we are talking about the file size?