the title says it all. if you're guessing that the article on famitsu's 3ds software reviews had anything to do with this question, you're right.
to a certain extent, i would say that ratings give me a semblance of idea on what or how much to expect from a game. at the end of the day, though, the only way for me to determine whether or not i agree with the rating is to ultimately play the game for myself.
there are some cases, however, where i don't bother with a game (or a film) just because the reviews suck. sometimes i regret it, sometimes i don't.
what about you? how much of your game purchasing decision is based on what you read from reviews?