I love doing these types of comparisons. One thing I will note is that I managed to find Cloosterbitter at a Mission Liquor.
Speaking specifically about the Cloosterbitter:
70% sweet
30% alcohol forward
Nose is 65% Fennel bulb forward, 35% Anise
Taste is 65% Fennel bulb forward, 35% Anise
The overall taste is similar, like, but not exactly comparable to Green chartreuse. But if someone's looking for a sweet green chartreuse substitute in a mixed beverage, I'd say give this one a try. It's affordable.
The overall taste is definitely akin to that fennel and a niece flavor. If there's any sort of black licorice flavor in here, it's very subtle, less than 1%. I would say in terms of pepper, maybe less than 1% as well.
In summary, I wouldn't call it out of this world. But if you're into that a niece and fennel flavored liqueur, give this one a try.
I did a video about it here
https://youtu.be/NBxTgimRcAk