Reading through, I see a few people saying that Metacritic is bad. In my opinion, Metacritic is only bad if you really believe that a singular, scientifically objective measure of game's quality that is universal to all gamers(that is, independent of their own personal preferences, biases, and tastes) to the precision presented(Metacritic has a 1 in 100 precision; I have seen some sites go as far as 1 in 1000 precision) is possible and valid. However, if you believe that it is possible to have a singular, convenient place in which to read multiple different opinions regarding a game, then Metacritic succeeds beyond a shadow of a doubt as an aggregator.
In dealing with game reviews, one really has to have their Bullshit-Meter(TM) well calibrated to filter out reviews that are overly biased in favor or against a game for reasons of vested interest, agendas, or just plain ignorance. This means the gamer has to carefully read through the reviews and make judgements regarding the quality of the review and its credibility. In part of making this judgement, he may have to mentally adjust the review's score up or down based on text of the review; this is especially true with these attempts at such high precision in the score. He may then have to make further guesses whether the game is something that would appeal to his own personal tastes because that is critical information that often gets left out in reviews, especially user reviews; the reader generally has to read-in-between-the-lines to make this determination.
While I'm on it, the current high precision(1 in 10 and higher) of most individual review scores is, in my opinion, a false level of precision. Any individual human can really only distinguish at most 6 levels(a 1 in 6 precision) of quality: excellent/perfect, good, okay/passable, mediocre, bad, and shitty/unacceptable. These levels are not objective and universal, nor do they necessarily exist on a linear scale. The may change from person to person and circumstance to circumstance, depending on the tastes of the individual and the criteria, constraints, and restrictions applied to the game. It is necessary to full qualify each judgement of quality to avoid ambiguity and miscommunication. While it is true that averages can have a much higher precision than the individual values that went into the average(the more values, the higher the precision of the average), an average losses a lot of information and cannot be used by any given individual as a litmus test for whether the game will be something they enjoy and find worthy of purchase.
Basically, the entire game industry and game community have, in my opinion, fallaciously assigned more meaning and precision to review scores than is reasonable. It is little wonder that the system is not working so well. We wanted something quick and dirty, but that simply may not be possible; certainly, our current implementation of such an ideal is proving horribly flawed and invalid. Honestly, in my opinion, the entire game review process and methodology needs significant revision.
But, returning to the point of Metacritic. In my opinion, Metacritic is fantastic if used properly and within the context for which it is valid, and that is as a single, convenient place to find many different opinions and reviews of a game, both professional and non-professional. If Metacritic is used to obtain a singular, objective, universal metric by which to measure a game's quality, then it will fail, miserably.