I would say that the other interview postings are very accurate and similar to my experience.
There are three main steps to the interview process. I sent in an initial application with a CV and cover letter. The following morning I received a PDF prompt asking me to answer several questions/ fill out the form.
After submitting the form I was invited to an initial interview. This interviewer was very upbeat and positive. It was mostly generic interview questions - nothing too difficult.
I was invited to a second round interview the following week. This interview has considerably harder questions. I was asked to work through two lobbying based scenarios. It was one of those things where I would give a response, and then be told that wasn't going to garner enough support and what else I would do. The interview felt relatively solid, but it was definitely more challenging than I would have expected for this job position.
A week later I received an email referring me to a different job position that I was not interested in.
Just a side note I found a little odd - I was originally unable to schedule an interview because they had so many applicants... but a job posting for the same position I had applied to was posted on another job board three months prior to my application. When I was referred to another position (with a sister non-profit, not Environment America) I wondered whether they were using these job postings to get applicants in the door.
I doubt I would apply to another position at Environment America.