As I suspected from the preview, the Mayans aren't very good. I mean, if you happen to get a bunch of planations placed in just the right configuration, they're fine; but that's 20% of games. There's no such thing as a resource bias, so you don't get plantations more often than any other civ. From the half-dozen games I played, they don't even seem to get any noteworthy rainforest bias. I think I generated something like fifteen maps and maybe five or six of them had rainforest within reach of the start location. Only a couple actually started in rainforest. Quite a few of them literally had no tiles within immediate reach on which farms could be built, which basically meant a forced restart or multiple turns spent moving the settler through rugged terrain. There were more games without plantations than with.
Just for the record, there very much is such a thing as a resource bias. And indeed, Maya has a tier 2 bias for plantation and mining luxuries. I'm not sure why they added the mining luxuries, but whatever.
Maya also has a tier 1 (strongest) bias for plains and grassland, not for rain forest.