Tonina is a stopping-off point on the way to Palenque that houses some mediocre Mayan ruins. It's like the speed bump on the way into the parking structure. You may as well take notice because you're going that direction anyways.

So Tonina is not nearly as impressive as Palenque but to its credit it is very low key. The area is self-guided, not overcrowded and everything is accessible. You can kiss bas-reliefs, you can get lost in the jungle and you can scramble over pillars. And on the way out they'll sell you a soda at the caretaker's house/entrance gate.