Windows Media is still a poor video compression format
For example, I recently compressed a few video clips for a client with high motion in QuickTime with Sorenson Pro (the codec generally used for movie trailers) and WM. I was able to get total bit rate with stereo audio at 320x240x30fps to around 120k with only a few minor compression artifacts. To get the same level of quality on WM I had to get the bit rate up to around 400k. What's up with that?
The funny thing is, Sorenson Pro 3 has been out now for at least three years.