Darkseid is my favorite comic book villain, not just because of his aspects, attitude, powers and temper, but also because of the anturage, let's say. Brainiac is the first villain ever introduces in the new Superman series, so he really should have been on the series.
Anyway, the episode was really nice because it not only showed a team-up of my 2 favorite villains but it had two twists: Brainiac being Darkseid's ally and Darkseid getting his own way as usual.
This episode is also important for character developement, because New Genesis is destroyed and Darkseid is left to his appparent death.
The action is nice, the battle with the 100 Brainiacs being rather nicely done. All in all, a good episode that is a must see, especailly because it will have future importance.