I'm playing the beta version, which has the "Caves an Cliffs" options, but as soon as I turn it on, the world generates with beautiful Cliffs, but no caves, (there are some caves underground, but) none of them has an entrance above ground.
So basically these worlds are unplayable in survival
I tested multiple worlds with my friend, and none of these world had cave entrances above gound
So we started to dig down and we did find caves. They weren't big but they had some ores and stuff
And we find caves as well below 0 but they had nothing in them. No water, no lava, no ores.