Was your motivation to go through another intermediate on top of mturk because Amazon does not deliver its mturk service to European companies or for another reason ?

Did you find out if the CrowdFlower workers are more/less expensive compared to mturk (excluding CrowdFlower charges of course)? What I mean is there might be people wanting to work only under CrowdFlower's umbrella and asking more for their (proven) quality work.

The video is actually really impressive.