Correct me if I'm wrong... but Metacritic only collects reviews and gives people an overall average (As well as links to those reviews)... They don't make money off scores being good or bad, they make money because they consolidate everything into one location.
It's publishers and marketing firms that hand out bribes for good reviews.
That said, I never judge a game by a "commercial review" (Meaning a review done by a "professional" publication), I really only read/watch their reviews to get an idea of what the game is like... not to judge if I'll enjoy it or not.
If anything, I'd much rather judge a purchase off of independent reviewers (Such as the reviews many people put up on youtube) as they wouldn't have been paid off for good scores, and they are less (generally) less jaded about gaming as it isn't their job to give scores to newly released games.
Overall though, I've purchased games that have gotten scores in the 2/10 (Commercial or user) and enjoyed the game much more than I would a game that got a 10/10.
Reviews, commercial or not, are opinion (Swayed by bribes or not), and should be treated as such. It doesn't matter how "professional" a game reviewer is, there will always be personal bias involved. Everyone has different tastes, so I try a game to decide if I'll enjoy it or not. Honestly, I think most reviews are nothing more than additional publicity for games.