I actually think the links that @AuraObscura provided look super helpful. They have a variety of different perspectives and offer some in-depth discussion of some of your questions. Some of the forum discussions especially are really enlightening because they have participation from current MDs and CNMs who discuss their work and life and such. I highly recommend reading through some of them. For example, the AllNurses and Mothering forums have several responses from CNMs who discuss how many hours a week they work and the variability in schedules based on where they work.
I am struggling to come up with responses to your question because it’s so undefined - it’s difficult to give “general knowledge.” I’m not a nurse-midwife or an OB/GYN so I can’t tell you what working the job is like; I can only give you the second-hand knowledge that I learned from searching the Internet and reading forums and chatting with gynecologists and nurse-midwives I know and met offline.
The basic differences between a gynecologist and a CNM (I addressed several of these in the first post I made):
-OB/GYNs go to medical school + a residency. CNMs are nurses with a master’s degree. That’s 7 years of training vs. 2, although most CNMs do have work experience between the BSN and MSN.
-OB/GYNs make more money but also tend to have more debt.
-OB/GYNs work under the medical model; it’s a disease-focused model that has an eye towards what’s wrong health-wise and how to fix it. CNMs work under the nursing model, which is more patient-focused, holistic, and values patient and family education. Neither is better; they are just different, and it kind of depends on what you want to do.
-CNMs tend to handle more routine pregnancies and childbirths - ones with no or few complications. OB/GYNs can handle pregnancies and childbirths that range the spectrum from very mundane to very complicated. If you think you might want to handle complex or potentially dangerous cases then the MD is the way to go.
-CNMs tend to use less intervention in their work. That’s partially because of their general nursing philosophies/model and partially because they have less complicated cases to work with.
-Both CNMs and OBs can have their own practices. But CNMs can also work directly for a hospital or for a doctor’s office.
-Although CNMs practice independently, some states require them to practice “in consultation” with an OB. Some malpractice insurers might also require this. (Note that malpractice insurance for working with pregnant and birthing women is very, very, very high - because these patients are probably the most likely to sue if anything goes wrong.) That may simply mean meeting with an OB colleague a couple times a month to discuss cases and get some insight.
Hours vary. One of the great things about the nursing profession is the flexibility. Some CNMs work regular 9-5 hours, 40 hours a week, in a doctor’s office or in their own practices. Some CNMs work part-time for practices, hospitals, or birth centers. Some CNMs work three 12-hour shifts a week at hospitals or clinics and that’s considered their full time work, but they can also pick up overtime here and there. Some CNMs combine roles - so for example, they may work part-time for a hospital but also pick up a few hours a week doing home health visits for homebound women, for example, or they may teach a few classes on the side for extra money. Some CNMs do what’s called PRN work (it’s basically variable schedule work, as-needed) and so their hours vary per week. It really depends. You can probably work as many or as few hours as you want.
I get the sense that more OBs tend to work more regular hours (40-60+ per week), mostly in private or group practices. Some OBs work for practices that are owned by hospitals. Most OBs do some rounding on labor and delivery floors occasionally or regularly. I don’t think there are many OBs that work part-time hours, but I could be wrong - it just depends, I think.
One thing to note is that both OBs and CNMs have a higher-than-average likelihood of working some irregular hours, since babies don’t know what time it is when they want to be born 
So the likelihood of being on-call at 3 am or having to dash into a hospital or birthing center at 11 pm or 5 am or whenever is pretty high.