As far as I know, all chasiduses agree that the Maggid of Mezrich was the primary student of the Baal Shem Tov. But I was listening to an online shiur about Chabad (Lubavitch) history, which conveyed the unmistakable message that the primary student of the Maggid was R' Shneur Zalman of Liadi, known to Chabad chasidim as the Alter Rebbe. According to this shiur, not only was he the primary student, but the relationship between the Maggid and the Alter Rebbe was of a much higher level than any other student.
If I were a follower of another chasidus, wouldn't I feel uncomfortable with this view?
I was wondering if perhaps this is similar to (l'havdil) the situation where the Torah says Yitzchak is the favored son of Avraham, whereas the Koran says that it's Yishmael; do other chasiduses claim that another student was the Maggid's primary student? Or perhaps other chasiduses also trace their "chasidic mesorah" through the Alter Rebbe but it splits off at a later point?
So my question is, what is the point of view of other chasiduses regarding this "chain of mesorah"?