Or is the foreign teacher better off without them in the classroom?
Before beginning my experience as a TESOL teacher in Thailand, way back when I was a newbie farang taking my TESOL course on Phuket, I was repeatedly assured by indifferent agencies and instructors not to worry because you will always share classrooms with Thai teachers that are there to help you.
Differing techniques inside the classroom
In my experience, students recite a grammar rule or know the rule or learn the rule and maybe even vaguely understand the rule, but then you ask them a basic question and they don't understand.
What are the disadvantages of being an English program teacher
Since I've been teaching in Thailand. I've by chance and not necessarily choice - always been placed in English Programs. English Programs are immersion-based ‘special' educative programs placed within government schools.
Why choose Thailand over other TEFL destinations?
Now, more than ever, being a native speaker of English (Or even non-native speaker) is a valuable world export and can be an easy, economic, and deeply rewarding way to see the globe.