method of TEFL

Which one is better English tough by native speaker or English teacher ?

My opinion , better or not is depends on the student's ability in English.
Why ? My reason,generally, used native speaker depends on the policy of department or the school. For example, in SMP Negeri 4 Surakarta especially special ( Emercy class ). The special class is a program for students which in everyday teaching and learning process use native speaker. The students can understanding about what their teacher says, because the students have good ability in English. The background of native speaker as a teacher, so she / he understands about the culture of her / his student. But, if the native speaker isn't a teacher so, it is a difficult to convey the materials clearly for them.
We can observe the progress of English teacher, in fact, English teacher couldn't good in English .
Give a note, for example pronunciation. English teacher has an accent self. There are Scottish, British, etc. The problem is there is English teacher inconsistent with their accent causes their pronunciation worse. But also, native speaker isn't always mastery the grammar, for instance, American isn't mastered the grammar.
my conclusion, I think it is better to find native speaker because students can be more motivated to study English. It is no problem, difficult or not depends on our as teacher.
So, teacher should be know an appropriate method and techniques to teach them.

Thank you...