You are right that on the economically side the reporting and research, indicates that there is no measurable difference on economical performance between before and after law. But before the law was introduced there was worry that an influx of unexperienced women would undermine profitability, which did not happened.

The positive, (as seen from most Norwegians view), is that there are now more powerful women in Norwegian industry and private sector. This is obviously an ideological view, and if you view more women in powerful position as of no or negative value. Then it isn't a positive for you.