The mere fact that SpeedScreen actually is comprised of several different technologies only emphasizes the fact that the SpeedScreen set of technologies is indeed underestimated. Did you know for example that SpeedScreen Browser Acceleration does:

• Optional automatic disabling of GIF animations. 
• High-level browser hooking
• Dynamic JPEG image recompression
• Background image delivery
• Client-side image caching

I know some people do not. SpeedScreen Browser Acceleration can really make the Internet Explorer experience on Presentation Server a lot more bearable. In his post Derek refers to some research that was done when SpeedScreen Browser Acceleration was released for the first time (5 years ago). The research states that SpeedScreen Browser Acceleration enables "200% to 250% more efficient network bandwidth utilization than locally installed browsers (depending on the configuration and tuning options selected)" and "may provide users with a two-fold or greater increase in page loading performance" on low bandwidth connections.

I would not go blind on these numbers. Like the last three words state, it is indeed very much dependant on the network you are "browsing" over. The effect of SpeedScreen Browser Acceleration is (much) lower on today's high bandwidth connections. After all the report is more than 5 years old. Still, SpeedScreen Browser Acceleration is by far the most sophisticated set of technologies to optimize the Web Browser experience in Windows based Server Based Computing environments. I think it is good to see that Derek does not forget to mention that the absent of support for more modern components of today's web pages like Flash and PNG is something that kind of limits the potential of offering Internet Explorer via Presentation Server. 

Be sure to read Derek's entire article: The Multiple Facets of SpeedScreen Browser Acceleration.