Can't wait to try this out!
I've prepped and am getting ready to run Masks of Nyarlathotep within the month and Occultation is my preferred set of rules for it. I know it may be a tall order for such a long-running campaign, but I am eager to find out what happens (har har).
The only thing that has come up so far is practised story game players asking about things such as Conditions, and I'm suspecting that with a long running game this may be necessary to track things such as consequences from taking risks and whatnot.