I have both, but only used the ISACA materials to prepare for CISM. Of course the knowledge from my CISSP studies plus experience helped, but I did not use non-ISACA study materials for the exam prep.
I did the opposite. Sat for the CISM first as prep for CISSP and used materials strictly for those certifications. Had to make sure that I can look at the big picture first before attempting CISSP given the huge difference in scope.
I passed the CISSP and studied a LOT for it. Then I sat for the CISM a few months after and passed without additional reading, only doing some official practice tests (QAE). If I wasn't already in a "business security" role I'd had a much harder time.