Not sure what you mean. People score it based on a percentage. Because there are 150 questions, each question is worth 2/3 of a percentage point. As far as a "good score," that's pretty much subjective but 80%+ probably fits.
You should keep in mind that, even though these questions mirror the style of USMLE q's, this particular set is quite a bit easier than Step 1. I scored 84% in February before I did any studying for the boards and I now several people that scored above 75% before studying anything either. Pulling this stunt with a tougher set of questions is pretty much unheard of but not uncommon with the released questions.
