I have no data on this. But I don't find using YouTube unprofessional. Also, I'm not sure how embeddable your video will be, but as a blogger, I much prefer people using YouTube so those videos can be embedded easily, and playable on iOS devices.

S3 + Cloudfront. Many people use Vimeo as well, which has minimal branding and supports high quality.

I haven't actually used them myself, but Wistia does deep tracking of plays.

Vimeo all the way! Simple to use, looks great, comes up well in natural search results.

http://vimeo.com/plus

I've used YouTube for some video hosting on my website and don't believe it to be unprofessional. In fact, when requesting feedback on a landing page which showed the video, I never received a comment that would have implied YouTube hosting was anything other then acceptable.

I have always used Vimeo on the past for this sort of thing.

I definitely prefer it over youtube based on quality of video, bandwidth (a lot of youtube videos that I try suffer from playback issues), and branding.

Hosting on S3 or some other CDN is also an option if you don't mind paying a bit.

I personally hate vimeo because of their horrible fallback & lack of some forms of IE support.

If you're using IE without flash installed (in my experience), it defaults to a black background with black text on top. great user experience.

Host the video file on Amazon S3 and then use something like JWPlayer to show the video on your website.

Vimeo is a pretty good option.