I have worked for both. Nuance is far, far worse than MModal. However, it is like being a slave in every way possible. You are basically not allowed to take your fingers off your keyboard. The pay is terrible. The work is terrible. I don't use the insurance but I have seen it and it seems expensive and not that great.
Being an MT right now is terrible no matter where you work. I stay because the hours I can work allow me to go to school so I can GET OUT OF THIS INDUSTRY.