I had a 4.7 Gigabyte .mp4 video file (one hour in duration) on Dropbox and used the "upload from Dropbox" feature.
This 4.7Gb file transferred from Dropbox to Vimeo in about 5 seconds.
I was kinda blown away at the speed. Very impressive!
Then it took about an hour to transcode for streaming.
Great work Vimeo !