Sufi-ism is a "pacified" version of Islam, often a stepping-stone to the more familiar, violent version of Islam. Most of the adherents of the latter kind of Islam reject Sufis as Muslims.
Was late Nusrat Fateh Ali Khan a Sufi? Sufis sound like Islamic version of Bhakti.
http://en.wikipedia.org/wiki/Bhakti
If the graduates from the Madrassas move toward Sufism, I would count that as a very very good trend.
Sufi muslim may be a path away from violent Islam.
The whirling dervishes use meditation as a direct path to divinity. Sufi refers to a cheap rough wool cloth, that constrasted with the luxury of the Sunni caliphs. Sufi was once a Shite thing, but now is more Sunni than Shite. Some suggest that it is a push back of Zoroasterism into Islam. Of course that would be a heresy, and others assert that Sufi is an independent movement within Islam.
1. Noone but me can eat my daily bread, so I am at peace.
2. Noone but me can perform my prayers and duties, so I am busy with them.
3. A man must be able to wake, sleep, eat, work, teach, and love, and never forget G-d.
Just a note: I am not a Muslim, but an interested observer from outside. There was a time that the Sufi schools were filled with perverts of all kinds, kind of like Catholic Seminaries. That time is in the past for the Sufi, or so I am told.