NaturallySpeaking is the world leader in speech recognition accuracy and ease-of-use.  NaturallySpeaking's BestMatch III technology combined with it's vocabulary build program provides 99% accuracy with-in the first hour of using the program.   With clear diction and using proper correction procedures the program is extremely accurate.   For the medical, legal, law enforcement, engineering specialties the accuracy is even better because the vocabulary is more limited than say--journalism which is usually very broad. 

NaturallySpeaking is the easiest program to use because everything can be done by voice.  You don't have to click on words to correct, it is done with simple commands.  You don't have to use the keyboard to add the spelling of a new word, just spell it by voice using the alphabet.  Even the mouse can be moved by voice using a feature called MouseGrid or another feature Mouse Up, Down, Right or Left 1-10.  This gives people with disabilities a completely hands-free environment.