I think they are both great careers in their own right. It all comes down to personal preference. I was choosing between the two also. I don't think that income and hours should be the only determining factor in your choice. There are many medical specialties that offers great hours and pay, such as dermatology, family medicine, radiology, plastic surgery, rhematology and the list goes on. As long as your specialty does not need the support of a hospital and you can open your own practice, you can have a good family/work balance.
I choose dentistry because I know I will be a better dentist then a doctor. I have a very extensive art background so I liked the hands-on, creative, and tangible nature of dentistry. It is not as easy to make money in dentistry as everyone says. We only hear about the good stories. You can get lucky and get a great associate job, but they are not always available. If you get a bad associate job, you can make as little as 80K a year. I know a dentist who got tired of working for someone and started her own practice. She LOST 60k her first year and is just started to break even after several years. Dentistry is also physically demanding, back, neck, and ankle pain, and carpel tunnel are common.
I think medicine is cool in a way it is exciting. LIfe and death situation gets the adrenaline going and you get to meet alot of "interesting" people working in the hospital. Also, if you have no desire to run your own business, medicine is great. . You just go in a do what you do, don''t have to think about expenses, overhead, hiring staff. I have a friend who is super good surgeon, but I don't know if she could run a business. She is finishing her fellowship in surgery. When she is done, she is expected to make 400K a year as an attending. Also, she will get paid time off to do research, present at conferences, and mentor incoming residents and fellows. The only down side is that you have to do a residency and fellowship.
Doctors like to complain because the grass is greener on the other side. One is not better then the other, it is just different.