Jarred Walton of AnandTech has written a comprehensive article comparing the speech recognition included with Microsoft Office (and the Tablet PC) to Dragon NaturallySpeaking (DNS). He provides a complete overview of each program and then proceeds to test the two methods for accuracy and CPU utilization. As a big speech recognition fan I found the most interesting part of the article to be the comparison of both methods at different dictation speeds. He makes some interesting observations, such as faster speech has a minor impact on the Microsoft accuracy but hammers DNS. The author also makes a detailed comparison of different accuracy level settings with both methods and the impact on both accuracy and CPU utilization. It is a very good comparison of the two methods and worth a read.