 Owned my 2005 Mazda6s Sport with 6 speed automatic for about a year. My reason for not giving higher marks in performance and "fun to drive" is due to the poor throttle response - delay when the accelerator is aggressively pushed.  This is one of Mazda's early attempts at an electronic throttle (i.e. driver doesn't have a mechanic connection with the throttle; the computer senses the throttle input of the driver's foot and then opens the throttle accordingly).  I did take it to the dealership and received the computer software fix which improved the response somewhat; however, the existence of this fix is Mazda's acknowledgment of the problem.