It takes a level of buy-in from players that is hard to get. I couldn't run it at my table for years due to having a few players for whom the magic system and general focus on esotericism were RPG kryptonite. The main thing I have noticed is that the game changes pretty dramatically at Gnosis 3, so I establish at the start that the entire cabal has to go from 2->3 at the same time.

I had to stop due to some IRL stuff, but I am hoping to start a new campaign soon or I might try running Mummy: The Curse since I find it really interesting.