I prefer the "join" approach for beginners too, but >>= has become so pervasive that I feel bad trying to explain it that way. Turning people loose on monad-heavy code with that approach still leaves them needing to convert their understanding into >>= anyhow.
One does wonder about the alternate world where that was the primary way people interacted with it.
I think you don't have to teach people to program with `join`, but just that `m >>= f = join (fmap f) m`. It explains away the "get a value out" question but teaches the most common function from the interface.