Avantages
Editing staff considerate and flexible. Pay is decent on a per-word basis. Up until a couple months ago, projects were plentiful for most freelancers. As long as you consistently turn in acceptable work, they'll work with you to get the projects you need to make a living and provide the support you need to do the job.
Inconvénients
In mid-to-late November, project availability took a sharp downturn. Now it feels like I'm crawling over a dozen other freelancers for the same four or five jobs per week. The editing team, normally very up-front, honest, and communicative, was cagey and vague about the sudden downturn in work. The work itself can be tedious at times and it involves the production of thousands of words per project (they have become shorter in recent weeks but still average over 2000 words per project). While the editing staff is usually supportive, they offer very little in the way of feedback for most projects. In the past year, I've gotten maybe two emails regarding suggestions for better future content.