I will start this by saying that I know I am a little biased, since I am an OB nurse at a hospital.
I have known someone who delivered at home. Her situation ~ she had a c-section with her first baby, this meant she was considered high-risk and never should have delivered at home. I have seen VBAC patients deliver successfully, but I've also seen the uterus rupture, which is why they're high-risk. Her "due date" was around Christmas, she delivered in March. (she had irregular periods, but with no testing/ultrasound, there was no way to verify her dates)...she hemmorrhaged after delivery. Her husband just about called 911.
I have no problem with certified nurse midwives. They usually work with a physician, just in case something happens and there is an emergency. They normally work either in a free-standing birthing center or in a hospital. But again, there is back-up available. Lay midwives usually do not have formal training. They train with another midwife who trains them. They sometimes are certified with the state, sometimes not.
I've been an OB nurse for over 16 years. In that time I have seen women who where totally low-risk patients who, during the course of laboring, somehow became an emergency situation. I have done CPR on mothers and babies who had zero risk factors. And yes, I have seen doctors call c-sections because they didn't want to wait, that irritates the nurses I assure you. My job is to be a patient advocate, help my patient in any way I can. Whether it's to help her deliver naturally with no medications, or to get her the medications she wants/needs to help her through the labor.
Unfortunately in today's age, most women do not take birthing classes, so when labor starts, they have no idea how to deal with it, so then they want an epidural, and they want to feel nothing....even during the early stages of labor. They lay in the bed, don't move/change positions, and the natural progression of labor doesn't happen, or doesn't happen fast enough, and they end up having a c-section.
Yes, having a baby at home can be a wonderful experience. Keep in mind, also, that babies are bigger than they used to be 100 years ago, and we are not nearly as active as we used to be, so all of that affects the process.
I wish your friend's niece good luck! I hope it works well for her :)
D.