It's probably better suited for #f1-discussion . There are too many factors to decide, especially for a car like the 2012 Ferrari.
#How do people decide if a car iswas bad?
harsh spindle
hot axle
a 'short and sweet' answer is that, as digmouse said, there are many factors of a car performance, and sometimes a 'bad' car can be the best at one aspect (think the Alfa Romeo being the lightest, or the recent past williams being very fast in a stright line), overall, a car is 'good' or 'bad' depending on where the team want/expect the car to be
The Haas, for example, is not the fastest car, but seeing the situation the team was coming from, it is a great car, you can see how satisfied Günther is most weekends