This arc started a bit slow but the final conclusion was phenomenal. I would argue that this episode is the best one in the entire show.
The martian racism can be bothered a few people because it could feel a bit forced, but to me it was a really fresh idea, specially because from season 1 we know that Mgan was bullied for being a white martian.
Aside from the policit martian thing that played in this arc, Beast Boy being afraid and traumatized because of the psychic attack feels real and natural and you get he has behaving like during the whole arc.
The ending of this episode is what makes it so special. They did deserve a happy ending.