I have found Siri pretty accurate in understanding what I say. She is only good for certain things though. For me, I learned I have to talk fast, because if I pause and think about what I'm saying she detects end of speech and she tries to answer the question or do whatever task before I am through. Overall I like Siri.
I gues it could be my connection, I have been having problems with the connection (iMessage not working, picture SMS doesn't load, etc) why is it like this??