The 32-year-old geography teacher qualified in June 2003 after six months of on-the-job training at Southfields community college in Wandsworth south-west London.
"I found it absolutely fantastic. You are thrown in at the deep end from the beginning," she said.
"You have the advantage of being in the classroom from day one unlike the PGCE where there is a lack of continuity with time in lectures at college followed by time in school. You are seen as a proper teacher from the word go."
Ms Viner dismissed concerns that school-based courses do not give teachers sufficient subject knowledge, saying that trainees have to have a degree related to the subject they want to teach.
She does admit that she has little experience of teaching outside the "distinctive ethos" of Southfields.
But that would not have been different if she had taken a PGCE, she said.