Pros
Earth Day has a young, driven staff who do a lot with a little. I made great friends there and I'm so, so glad that most of them have left. I also learned how to work in a hostile environment - managing up, staying out of view, and other office politics skills are handy, though I wish they weren't necessary.
Cons
Leadership invents a fresh way to sabotage their organization every week. It's impressive, but not at all fun. Whether it's calling at 2 a.m. with an "urgent" and terrible idea, disassembling staff achievements because they didn't think of it, hiring unqualified friends & family, or some other amazing failure, the leadership of Earth Day gives a master's course in awful management. Take the job if you're desperate, but start applying as soon as you join — everyone else is.