Vimeo is terrible, very anti gamer, to.the point they ban developers that put trailer videos on their service. I am personally very happy that YouTube now match Vimeo quality and happily hosts my trailers for me.
According to Vimeo's guidelines, you just can't upload gameplay videos. It says specifically you can upload first party videos but need to mark them to avoid deletion. With the huge community of video gamers on YouTube, I don't even get why you'd want to put that video on Vimeo.
When gameplay got forbidden, there was no such guideline, and YouTube did not supported HD, so Vimeo was popular for trailers, but their anti game stance drove everyone away, including first parties.
