Edelman landed at No. 5 on Glassdoor.com's annual "50 Best Places to Work" list, which is compiled from employee surveys.

Facebook topped the list, followed by Southwest Airlines, Bain & Company and General Mills. Edelman is the only PR agency in the top 50.

CEO Richard Edelman was given a 93% approval rating by staffers and the firm overall scored a 4.0 out of 5 on the rating scale.

One reviewer, identified as a VP for Edelman/Chicago, gave the pros and cons of working at the top independent firm. Positives listed were "incredible clients, very smart colleagues, management with great vision for future." Work-life balance was said to be a "struggle" by the reviewer, who advised senior management to "review work life balance on your team for more productive staff. Burn out is inevitable."

The top 10 in the survey were:

1. Facebook 4.6
2. Southwest Airlines 4.4
3. Bain & Company 4.3
4. General Mills 4.0
5. Edelman 4.0
6. Boston Consulting 4.0
7. SAS Institute 4.0
8. Slalom Consulting 4.0
9. Overstock.com 4.0
10. Susquehanna International 3.9

Update: Richard Edelman comments on the survey and says the firm has made great progress since 2000.