the greatest mekubal in the Arizal’s times was the Rema”k, R’ Moshe Kordevero zt”l. when he was niftar, the Arizal became the undisputed greatest mekubal of his generation.
the Arizal lived in Tzefat for the latter part of his short life, together with the greatest of greats, including the Alshich hakodosh, the Beis Yosef, the Chareidim, R’ Chaim Vital, among others. The Arizal was so great and so seeped in learning torah, his soul would join the yeshivah shel maalah when he slept. he would learn on one night what would normally take years worth of learning to accomplish when awake. That is the greatness of his talmid R’ Chaim Vital who able to transcribe the lofty, endless teachings of the Arizal.