When I was happily noob I saw a guy showing several "Mentors" groups on his profil. I asked around and someone explained to me that once there were those "helpers", then I supposed he was a good guy, but I noticed he was only showing to be cool, due to his long experience [and a "builder" activity]. especially among females newcomers. So, I always ignored him.
However one day, while I was discussing with some griefer, he suddenly blamed me as a "troll". I was surprised and asked what should be my purpose in that and he replied I was trying to be cute and attract girls(!). Shocked, I thanked him, in a Zen way, also to cut the conversation and moved away. For the record, I was used to play a game where I scored more than him. After his "lesson" I googled his weird legacy name and the only precise result was a terrible racist porn, later deleted. Finally I blocked and derendered him.
Another time I met a woman who claimed she was a mentor and she pressured me so much that I had to escape. Since then, when I hear the word "Mentor" I run away like if there was some of my stalkers. By the way, disappointed for the uselessness of reporting harassers, after turning one yo in SL I downgraded to a basic account and rented a home from Prokofy Neva. That first day a Linden appeared over my home, flying - I felt so done neither wondering why he was there and I teleported away. Prok impressed me for being professional (you know landlords...) and detached. In the specific moment, that mood helped me a lot, more than a Linden or a volunteer could do, so much that later I upgraded to Premium again...
That's my experience, this thread is old but I think that a Mentor can't be trusted, while I learned more from few true friends and particularly special ones.