World Resources Institute reviews

Lacks diversity or any sustained effort to actually practice diversity.

If you're lucky enough to have a good manager/supervisor, then your work environment will be more or less good and conducive to learning. But that's not always the case for many--if you're junior level and good at your job, managers can get comfortable pretty quickly and can hinder your professional growth. There is also the work/life balance issue--many managers don't hesitate to e-mail late in the evening (even well after midnight), and have you work when you're on leave/holiday. Plus, pay for junior staff can be pitiful, and they've made it very hard to negotiate salaries. Junior staff really bear the brunt of the work and are the lifeblood of the organization, but more often than not are not given the appreciation (and compensation) they deserve.