The Broad Institute reviews

This is where staff scientist careers go to wither and die. There are people at the Broad who have had excellent carrers as staff scientists but they joined when it was growing. Now it is a large institution and most of the leadership positions go to tenure track faculty. It is difficult to get supervision experience and so when there is a rare staff management position they often hire from industry. As a result, there is no real career path for staff scientists. The Broad also has a track record of laying off people who were good and had worked there for 10+ years when grants ended because there was no cooperation between departments filling open positions. Some departments are better than others, but unless your 10 year plan is to be scientist II, you might be happier somewhere that supports growth and pays (you) better.