Glassdoor does not vet people who claim to be employees and leave reviews. That is the biggest issue. After never checking for years, we were surprised to see strange reviews on Glassdoor about our company. Some were just written badly and didn't even reflect positions that were in the company. Being naive, we spoke to consultants who aimed to improve these reviews or remove bad reviews for a fee, and guess what - the reviews got worse. Then these consultants would email us about how bad our rating was, presumably to prompt us to hire them to improve our rating. Glassdoor has no transparency and no means of addressing these issues. It's a vicious circle and cycle. Avoid and ignore.