You can come across a lot of nothing. That's not to say it's empty, but in-between the lava lakes can be rather expansive. Much more so than in Minecraft. It gives you a much more terrifying and expansive place though. I don't want to spoil the experience though, so that's all I'll say. Try it out, by default it will spawn pretty high up in your world, so maybe try in a test world first to see if you like that depth, then configure it if you don't.
You can come across a lot of nothing. That's not to say it's empty, but in-between the lava lakes can be rather expansive. Much more so than in Minecraft. It gives you a much more terrifying and expansive place though. I don't want to spoil the experience though, so that's all I'll say. Try it out, by default it will spawn pretty high up in your world, so maybe try in a test world first to see if you like that depth, then configure it if you don't.