I've in a project about learning english, I want known your opinions about the difference between native english teachers and Non native english teachers.
What is the difference? what it's better? Why?
English is not the first language of non-native English teachers. For example, your native language is Catalan. If you went to school to become an English teacher, you would be a non-native Enlgish teacher.
I was born in Canada, I am a native English speaker. If I decided to teach English, I would be a native English teacher.
Who is better? No one is better than any one. I could be a native English teacher, yet not be able to grammar as well as a non-native teacher. Not everyone can be a teacher, and you will not like every one. Find some one who has proven they are capable of teaching (look for student reviews or their educational background) and someone who you feel comfortable with - don't judge them on whether English is their first or second language. :)
Sorry to say, but this is weird question. There is decisive difference, because native speaker will always be better than a non-native one, yet even the most fluent one. But personally I would prefer to have a fluent teacher who knows how to teach (not only English, but any kind of language)than native speaker who has no idea how to teach.