I can't speak well of any review outlet, personally. Find a writer you like and go by that, though unfortunately they aren't always going to be reviewing the games you're interested in.
I'm a fan of any scoring system that's well explained. The "school grade" percentages works, but with it you're basically working with scores from 6-10 (6 being poor, 10 being a masterpiece, anything below 6.0 is probably a broken piece of software) -- which is why many reviewers use a decimal system because there is indeed a world of difference between an 8.1 and an 8.6 provided the reviewer isn't scoring out of his ass (they all are, though).
I guess what I'm getting at is scoring can work provided the critics aren't retarded. Pretty much every magazine is corrupt to the core, and mainstream gaming sites seem to pull people off the street to review their games.
IGN is probably the worst, followed by Gametrailers. Eurogamer is basically a blog site where no real reviewing takes place, and I don't think anyone feels that Gamespot is a real site anymore -- every single game that gets released is an 8.5.