Can non-native speakers of English become good TEFL teachers?

This is a source of constant debate in the TEFL world. Here in Spain, many Spaniards (employers and students) request native speaker teachers. They hold beliefs, or prejudices, such as:

British speak proper English not like Americans

My German / Dutch /Spanish teacher of English knows grammar but speaks with a terrible accent

I want to speak proper English like my British / American/ Australian / teacher

This is a complex and controversial topic and I don’t presume to know the answer. In fact, I’m not exactly sure how we can define native speakers anymore. What I’d like to do is present both sides of the argument and let you make up your own minds:

Native Speaker Teachers are better because….

• They provide accurate pronunciation models for learners
• They can explain lots of idioms and colloquial phrases
• Students will use their English to communicate with native speakers
• They can show me how to use the grammar in the way it is actually spoken / written

Non-native Speaker Teachers are better because…..

• They use an international form of English that can be understood by everybody.
• They don’t use these idiomatic English. They can communicate clearly and unambiguously.
• Students will use their English to communicate with people from all around the world. English is now an international language.
• They had to learn it as a second language so they know how to explain it in a clear and accessible way.

What do you all think? 

What other reasons can you think of why native speakers or non-native speakers make better teachers.

We love to know what you think so please add your comments.