Osteopathic physicians earn the degree and title of D.O. Optomatrist are O.D.'s. O.D.'s have only very limited perscribing rights (I think the exact perscribing rights vary from state to state) and practiced in a very limited scope of medicine. DO's have full perscription rights in EVERY state and practice the full scope of medicine and surgery.
DO's and MD's will both perscribe pharmacotherapy in any instance where it is indicated. The over use of pharmacueticals by ALL physicians has become an issue.
Further, when was the last time you heard of a drug company running a hosital or clinic?
Now, in terms of a DO being less likely to be hired for a job, that is going to vary by region and type of position being applied for. In general, DO's have a little bit harder of a time getting hired for academic positions and on the west coast in and in the south. For all other jobs, it boils down to quality of the applicant, no the letters behind their name.
There you go... my two cents... and you got it for free!