I kinda liked the Trolls because they didn't have one trait like other alien races in fiction and I thought the blood caste system was unique but that's really. I don't really care about how they breed or fall in love, I never cared about that stuff. (Gamzee is literally trollege by the way)
I like the Carapacians more because of how unique they are. They are a species that doesn't breed, are the same each session with differences depending on the state or prototypings and have a very distinct look that separates them from other fictional aliens.
That's my opinion anyways. (Am I making too many threads?)
By the way there are secrets if you highlight some of the blank spaces.