I confess that, while I own a few sourcebooks, I’ve never actually played Call of Cthulhu, and read through Masks ofmostly because I’d heard several places describe it as the “best tabletop RPG module ever.”
It was . . . fine, I guess? Some fun ideas but definitely dated in its horror, even in the ultra-updated, this-time-we-took-almost-all-the-racism-out-we-swear edition. It definitely is long, though, and requires a play-style I couldn’t imagine coaxing out of any of the TTRPG groups I commonly play with.