I prefer to see a DO whenever possible. In my experience, a DO seeks to find the cause of the ailment, and offer preventative measures to keep it from occurring again - changes in diet, exercise, attitude, environment - whatever. For general maladies, such as flu and bronchitis, I find that the treatment I've received from DOs gets me back up to speed quicker and better than being treated by MDs. Also, although DOs certainly may prescribe any medication, I find them less likely to prescribe medication to treat symptoms than MDs. I'm just not big on medication anyway.
However, MDs with expertise in a narrow field have given me very good treatment as well. Iowe my life, literally, to a couple of MDs. Pending the results from some testing I had done earlier this week, I may need to add another one to the list.
The key to any health care choice is that it's YOUR life and well-being that is at issue. You need to be an active participant in your own diagnosis, treatment and, most importantly, prevention. Such self-advocacy is made much easier if you have a comfortable relationship with your primary physician, be it a DO, MD, Witch Doctor, Shaman or Snake Handler.