@Khuutra: It's not hard to be better than Mirror's Edge. It's not like "Party Babiez is as good as Mirror's Edge" is any better, is it?
I like the 100% method. It's best for comparing. What is easier to choose between, 94 and 89 or A- and A-?
Of course, you still read the review, but scores give an at-a-glance impression of the quality of a game. Also, with the letter scale, only the A and B scores are ever used. And most of us have no idea what they mean, other than Metacritic's awful A+ = 100, A = 100 chart.