Glassdoor is still useful in the sense that you can filter down to the worse reviews. Ignore those that are obviously sour grapes, and get a sense of how bad things are. I see a lot of things like:

Positive Reviewer - "Hypergrowth company! Lots of opportunties, great culture!!!!"

Negative reviewer - "They hired too fast, have no clue what they're doing, and have lots of free food and ping pong."