This is a really good idea. It just so happens that I'm in the market for a motion designer or animator for a TV commercial I want to run.
I didn't know exactly where to search for any talented designers, and eLance, along with some of the job boards, really don't give you much material to review. But I like this setup at first glance, and the quality so far seems to be pretty good.
I might actually find who I'm looking for through this service.