which one is better english is taught by native speaker or english teacher?

I think better to learn english to english teachers a lone , rather than to native speaker. Because , i think are more teachers know his grammar,stucture. Whereas the native speaker in my opinion is only good in speaking , he can speak well but not necessarily correct grammar and structure of this . Talking to native speakers is a great way of improving your spoken english , but native speakers of then don't ralize that things they consider" simple " may be very difficult for english learners.