The authors clearly know a lot about Mayan archaeology, like on a grad student level. One of my players studied Mayan archaeology and so did I and the fluff really holds up. The handouts are extraordinary, lots of glyphs and everything really looks like real archaeological research material. Lots of handouts means a few red herrings that my players turned into a whole other act of the campaign (a trip to a town in Lovecraft Country).
It's a good 1990s or modern campaign, of which I haven't found too many. The story is very good, very suspenseful. The plot can get convoluted, but I only found one loose thread. I think we did it in six sessions which is pretty good -- there's a lot of meat in this volume. Plenty of sections of texts to read to players, I always knew what to say. And the ending; well, this is a campaign that is actually scary, no matter how jaded your players are. Full marks. One of the best campaigns I've seen for any game.