A good four part series, and a must read for true Mass Effect fans. Much like the novels, this does a good job of filling in some blanks and delving deeper into the Mass Effect universe. Also like the books it remains very vague as to specific details in the games, meaning that it doesn't conflict with any of the choices the player can make (there's even a little jab at the whole Shepard being either male or female aspect).
The art is generally well detailed and fits the universe, though character models don't always remain completely consistent throughout (Liara's face can vary wildly even on the same page, varying from looking dead-on to almost nothing like her at all). The story isn't earth-shattering fantastic, but more than does the job it needed to. Most importantly it explores why Liara's personality was a lot darker and more sinister in the second game compared to her gentler and somewhat naive personality in the original.
With news that the comics may continue on beyond this, perhaps we'll see more of this, or perhaps the adventures of other comics (there's already been an 8-page freebie up at IGN since exploring a small piece of Aria's life).