If you enjoyed the first person Desmond portions of Assassin's Creed Revelations then you will also enjoy this. If not, then stay away as this is more of the same. The main reason to check this out, and this DLCs strongest aspect, is its story. Subject 16's tale is fleshed out nicely and you gain new insights on Lucy, William (Desmond's father) and Abstergo as well.
However, I can't recommend paying full price for this. 10$ for ~2.5 hours of content, including seeking out all collectables, just isn't a good deal in the video game genre. Then take into account the mediocre gameplay and sometimes overly simplistic visuals and audio and you have a product that is very borderline in whether to recommend it or not. I do appreciate the abstract art style but I think they did them better in Desmond's story. The same is true for the audio, particularly the music. That never grabbed my attention, unlike with Desmond (I loved the club scene).