Cnet is a great source for reviews on hardware. Whenever I buy a camcorder, I first go there to look up the reviews. This time, they did an excellent comparison test with HD videos between the most important video services offering high definition video hosting: YouTube, Vimeo, SmugMug, DailyMotion, BlipTV, Source and Facebook(which is not really a video service).
They added a neat roll-over feature in the article to compare the test stills (static images) between these services. You move your mouse over service of choice and the image changes. It is a fast and easy way to compare the compression quality.
Surprisingly enough, YouTube made a serious come-back from having the worst quality compression of all in previous years to one of the best today. Since they introduced HD video they did a real effort to enhance quality, which is not easy for a network that probably has the biggest load of videos around. (It reminds me that I will have to adapt my information on YouTube). According to CNET, YouTube was the winner of this comparison test, due to the extras you can do with their player, which indeed are substantial. Vimeo was the winner last year.
Anyway, here is the article:
http://news.cnet.com/8301-17939_109-10150445-2.html?tag=smallCarouselArea.0
Read also our own article: HD video on the web is not all sunshine which explains about the problems with HD and how to use a workaround for your viewers with slow internet connections.