This really is such a vexed issue. Pema Choepel has given the advice on another thread that it's better to go for a lesser known teacher you can have more regular contact with ie local. However, in my part of the world things have gone wrong with three (tibetan) teachers, two of whom I know quite well and both would have considered me their students. This makes me quite glad that my main teacher is the well-known Tibetan lama and filmmaker, even though it's highly unlikely I will ever have the same kind of access to him (in this lifetime at least).
When I think about it, one of the qualities these teachers lack is the incredible patience of the true master. It reminds me of the comment about Dilgo Khyentse Rinpoche, which says that whatever people said to him good or bad, he would just say 'I see, I see'. I also agree with smcj's friend's point about the eight worldly dharmas.
What I find curious is that students of these teachers sometimes turn away from the dharma altogether. I guess it's because once you really commit to a teacher you put so much trust in them. This is a case where trust the teachings not the teacher applies.
If you’re practising Dharma, you practise it for enlightenment. Not for rights, not for freedom, not for justice, not for healing, not for getting better in a worldly way.
~Dzongsar Khyentse Rinpoche