This is a perfect addition to the mass effect trilogy. The story of how Vega defeated the collectors provides an excellent insight into the sacrifices that were made to defeat the collectors. Vega's sacrifice was not in vain because it provided him with the inner strength to stop at nothing to stop the collector/reaper invasion. It's too bad so many had to die in order for the Vega character to become emotionally invested but in the long run the need of the many out weigh the needs of the few.
What's great about it: It depicts the very beginning of the collector/reaper invasion
What's not so great: Graphic wise I think it could have been better if the movie use the same graphics as the mass effect games.