This is my personal opinion.
There are lots of people who have a lot of trouble to get ATI’s proprietary video drivers working properly. Check out the Video and Sound section on the ubuntuforums.
Proprietary, patented optimizations are part of the value we provide to our customers and we have no plans to release these drivers to open source,” the company said in a statement. “In addition, multimedia elements such as content protection must not, by their very nature, be allowed to go open source.
Here’s some information about why open source video drivers are important :
The Role of Binary Drivers in a Free OS
Intel’s attitude is much better :
Intel releases open source i965 drivers!