Just Wow.... Probably one of the best DLC ever created.
The new characters are really well written: Idris Elba as Reed is such a good choice. The same goes for SongBird, who is really well written.
The story is really exciting and interesting. The tone of the dlc is different from that of the base game, but it's just too good, because it's so well done, the dlc really does feel like a spy movie.

Spoilers:
The choice between betraying Reed and betraying SongBird is so difficult, but that's what makes the dlc so good: you can't choose without regret.
I personally chose to betray SongBird (I remain loyal to my brother Reed), and so the final mission was really just SPLENDID : This final mission was both so stressful but also touching, with SongBird getting corrupted by the black wall. In fact, the moment when we have our last conversation with SongBird and have to choose between killing her or sparing her really broke my heart.

I don't know how the story ends if we decide to betray Reed, so I don't know if the last mission is as good, but this DLC is truly exceptional.
Congratulations to CD Projekt RED, who not only managed to "save" Cyberpunk, but also created the masterpiece that is Phantom Liberty.