I have completed two courses with TEFL: a 168-hour course, and Advanced Business English. Both are fairly thorough. I found the audio in some of the videos disappointing. Where teachers spoke, they were clear, but when students spoke, they were often inaudible, and I had to resort to the transcript. In the Advanced Business English, I would have liked to see more assignments, even though this was only a 30-hour course. I felt that something was lacking. I am still trying to work out what was missing. Once I put the pieces together and identify the gap, I will let you know.