I used to use Glass door extensively to vet potential employers. After starting at one company however I realized the problem with this.

Regularly in meetings the head of HR (which they called "People") would encourage us to go leave 5 star reviews on Glass door to help with recruiting efforts. It was really spun as a way to help the company.

The problem though is that this company had some problems, things I would normally expect to see on glassdoor. Because of the way they encouraged it, glassdoor was flooded with 5 star reviews that made it impossible to find any negative ones.

I no longer even check Glass door.