* Subject-verb agreement: The sentence is missing a subject. "Tastes" needs a subject to be grammatically correct.
* Word order: The phrase "among dark chocolates" is in the wrong place.
Here's how you can fix it:
Option 1 (More formal): "Of all the dark chocolates I tasted, this one tastes good."
Option 2 (More casual): "This dark chocolate tastes good compared to the others."
Let me know if you have any other sentences you'd like help with!