I personally can't stand the green chromis. They look like freshwater tetra's or anorexic goldfish and have zero personality - IMHO
. The blue are better loking fish in my opinion with more personality, although much more aggresive. Still, I don't think there's anything in your tank that will take crap from even a feisty blue chromis.
The yellow tail is among my favorites, and similiar in personality to the blue, but the yellow tail seems a less vivid color than the solid blue.