http://kotaku.com/5851157/ea-caught-pressuring-publications-over-battlefield-3-reviews
The article indicates a pretty well known problem with game reviews. The problem is simply that since the publishers are in control of the review versions of their games, that they can be extremely selective with who reviews it. To an extent it makes sense to weed out people who may unfairly represent the game, but then some companies take that bias into their own hands.
This combined with our perception of the rating scale technically being 0 to 10 (or 100) but requiring 8 (80) or higher to be considered decent causes a huge threat to validity. On a personal level, that combination makes reviews and ratings one of the very last things that I look at when making a decision.
--Zack