I experienced very slow speeds when uploading files to a small (m1.small) Amazon EC2 instance using the SCP and SFTP3 protocols with rsync, WinSCP and Tunnelier BitVise – around 30-40 kB/sec.
By simply switching the SSHd listening port to http (80), speeds went up to 1,4 MB/sec. Why Amazon would throttle the SSH port (22) I don’t know, but I hope this helps somebody else out there.