Um, well I buy no more than 2-3 games a year, and while reviews are horeshit for the most part they give a good indicator of technical qualities and if you find the right reviewer/persoon they can have similar tastes.
Obviously a game with average about a 4/10 isn't worth looking into if you are limited in what you buy and even if you played the game and think it is good theres no point risking £40 to prove that guy wrong.
No one uses opinions as the be all and end all but when your not rich as hell your not going to buy something just because its aliens