Should you host your videos on YouTube, or pay the fee to sign up for a dedicated content delivery network? Let's break down the pros and cons.
Cost: YouTube is free; CDNs charge a monthly fee. YouTube wins.
Services: YouTube offers only streaming video; CDNs offer streaming video, live video casting, video conferencing, pay-per-view video downloads and more. CDNs win.
Customization: YouTube videos are limited in length and play in Flash in a standard, branded player; CDNs allow you stream any length video in customized video players in various formats. CDNs win.
Video Quality: YouTube is getting better about converting video, but the quality can still be sketchy; online conversion quality varies between CDNs, but you can always use your own video conversion software before uploading. CDNs win.
Popularity: When your video is on YouTube it's instantly in front of millions of eyeballs, and indexed in Google; some CDNs offer video syndication, but mostly you'll be self promoting your videos. YouTube wins.
In the end it comes down to your purpose for uploading videos in the first place. If you're trying to make viral videos that will appeal to all audiences, go the YouTube route. If you're trying to communicate a professional message to a specific audience, using a CDN to stream the videos through your website is probably best.