All of the MD and MS degrees are very hard, but some require more skill and hours that you have to put into work. Because of more demand, some specialties are more challenging:

1. Cardiac and thoracic surgery

2. Neurosurgery

3. General Surgery

4. Orthopedics

According to research, most doctors get 2-3 weeks of vacation in a year. This is true despite of the speciality you get in.

Dentists and cosmetic surgeons get more leisure time (not "free time") because emergency cases are not that much. On the other hand, we have their medical counterparts as dermatologists and psychologosts, the same reason. More time on your hand mainly depends on number of emergency cases you get, which can soar high any time.