Vaji
There is give and take in both situations. The problem with non-native teachers is that when it comes to conversation and originality, they may lack the spontaneity of producing a correct answer in pronouncing certain words or placing the emphasis on the wrong syllable when pronouncing something which there are tons of them in English. However, when it comes to the concept of grammar and understanding the loopholes why some people do not understand certain things, a non-native does have more awareness of the problems and can handle the situation much better. The best scenario if possible would be to have both of them, a native and a non-native doing the work together. I used to teach English in Baton Rouge Louisiana to refugees who had come to the United States. I had a TA who read the text for me, the students repeated after her and then I continued with grammar and other stuff.