there really isn't a "Best" medical profession, its just what the person becoming the doctor is interested in. money wise, plastic surgeons or specialized surgeons make the most money, also private practice doctors make very good money.
The question should not be, which is the best educational program for a masters in the medical profession (for there are may good professions in this field); the question should be which one is the...
It really depends on what your intersets are in life. If you're worried about financial success - don't be! Everything will work out so long as you love what you do.