Vimeo tends to attract a high brow artistic crowd. The content is mostly art house, concept pieces, photo essays/camsots, and documentaries. Plus they only let you upload a maximum of 500mb per week with a basic account.
YouTube is all encompassing with it's content, from high brow to lowest common denominator. It's easy to produce a show and quickly gain traction, or just shoot some vids to share with friends and family. The downside being poor performance and the copyright police constantly trolling it for any possible infringement no matter how minute.
Blip has sort of become the go to for serious producers. Mostly due to their 50/50 advertising revenue sharing. The got a big boost when ThatGuyWithTheGlasses moved all their shows over to the platform.