A survey in which Siri, Google Now and Cortana users were asked to rate their satisfaction with their respective intelligent assistants found that Siri got the highest scores, with 81% of users declaring themselves satisfied compared to 68% for Google Now and just 57% for Cortana.
Survey participants were also asked to try out seven different requests and report on how well their service performed, as well as to note how many times they were asked follow-up questions. Siri had the lowest percentage of incorrect answers, and also asked fewer follow-up questions before it was able to carry out the task or answer the question.
Siri is definitely a feature that polarises users – some (like me) extremely satisfied with it, while I know others who report getting better results with Google Now. Microsoft is allowing a small number of iOS users to try out a beta version of Cortana for the iPhone.
Siri got the highest satisfaction score for setting an appointment, and the lowest for the question ‘When does Kung Fu Panda 3 come out?’.
You can see full details at the Experts Exchange site.