My son tried both foreigner and local teacher before. I found that some foreigner teachers hadn't much experience in teaching phonics and my son didn't enjoy the class. Therefore, I belieive the most important is the teacher's experience no matter the teacher is foreigner or local. My son now is taught by a local teacher and have no problem to communicate with foreigner.
I am looking for a local teacher to teach my son's phonics, if you don't mind will you PM me the information about your son's local teacher ?? My son is around 6.