Salaam, Brother what do you consider a "non-biased" source? I had a close friend from Lebanon that was a Habashi and prayed in the wrong direction? Is that not sufficient enough? He would not even perform prayers in the congregation with the rest of the Muslims? He said "Islam was spread by the sword." He allowed some sisters to sing in his Islamic lectures?? Brother, the scholars of alhus sunnah wa jamat has considered them as deviant. Inshallah others can shed some light. Also see this: http://naqshbandi.org/topics/refute/aicp/default.htm