Caves And Tours: Paradise Cave vs Dark Cave?

For those who’ve done both Paradise Cave and Dark Cave tours in Phong Nha, how do they compare? Paradise Cave is supposed to be stunning limestone formations-was it crowded? Dark Cave offers mud bath and zipline-was it too touristy? Which one did you prefer overall, and which tour operator handled both best? Did you feel rushed in either cave? I have time for only one cave tour and want the best experience.