I don't think ER should be the only thing you look at was part of my point. The other day Burnett pitched 6 IP with like 8 H and 6 BB and gave up 1 ER. I'm not someone who calls that a good start, that is a lucky start, it is bad hitting, it is a good result, but it is not a quality start. If he pitches like that every start he will have horrible results overall. QS is kind of like looking at AVG, it is sort of useful and very easy to figure out just by looking at a box score, but it doesn't tell you all that much. Something like game score is too complicated to figure out on the fly which is a big downfall but it does tell you a whole lot more about a start than QS does, it is kind of like OPS (I assume most people can't just look at a box score and figure out OPS in their head at least!). Not saying game score is perfect, just pretty readily available.