Why just one? Why not learn from everybody who has something of value to offer?
I remember when I first got started with Fernando, we were being trained by our MLM system. And we learned a LOT - in terms of personal development, mentality, etc. But they had nothing to offer in terms of doing business online so we had to look elsewhere (while still learning the personal development, mentality, etc. stuff).
We found Mike Dillard who was of GREAT help - we soaked up everything he's got. But we didn't stop there. We wanted to get into the nitty gritty of things on topics such as SEO, video marketing, pay per click, etc. So we branched out from there to fill in the gaps, to get even more "specialized".
An analogy would be Mike was our family doctor, and the others were like specialists (actually some of the others were also family doctors but from a different study).
The point is, each had something good to offer. And I'd be hard pressed if you found them all teaching on the same topic but straight out contradicting each other - and if they did, it's up for you to decide since it's probably working for them. For example, a mentor may say do blackhat stuff while another would say don't.
Up to you to decipher what are the pros and cons of each. A person can't know everything, so don't rely on just one person to fill in ALL the gaps for you.
Hope that helps.
P.S. That's not to say get paralyzed by all the different guru's content, but it is to say don't be afraid to make the "wrong decision" and don't be afraid to make MULTIPLE decisions.