If you write for Demand Studios, you know the good and the bad. They are flexible, you can have as much work as you want and the pay is pretty good. They have a lot of types of titles to choose from, and they pay often. However, the frustration level when you deal with them can absolutely and without question drive you over the edge. I often have to take a month or two away from them and do client work because I can't take the frustration level for very long.
If you work for them or have been thinking about it, this is all you need to see:
It's like someone opened a window into my soul.