I think it's apparent that reviewers can be persuaded to tell gamers that certain games are good regardless of the facts. Anyone ever play Azurik for the original xbox? The hype that game got as an RPG in gamer mags led me to believe it might actually be a good game.
I believe there are a few things to note. One is that everyone has opinions on everything. It could be hard to shake that for a fair review. Two is that they might risk the company not liking the truth of a scathing review. I notice that very few games in magazines rank below a certain score. If the company has an issue with your report, they could find a way to cease giving you the opportunity of reviewing their game.
In short, I would take a bribe. You're a reviewer who is paid to play games, obtain free swag for said games, and report to the players. I've never written to a magazine or editor to complain about someone's opinion of a game. That's all gamer magazines have become, ever since there were separate magazine for Nintendo, Xbox, and Playstation games. Even gaming websites all lean toward a certain company.
Seek the truth and play the games for yourself.