I'd agree with the above posts - both of these specialties offer very different aspects into patient care.
What do you enjoy?
Do you enjoy actually diagnosing and following a patient medically, and, if needed, surgically? Or do you enjoy immediate surgical involvement with the potential for very dramatic changes to functionality (or the converse with very POed patients)?
Can you actually manage a patient's diabetes while as an inpatient? Can you spell ACL? (sorry, but couldn't resist!) -
Seriously, both specialties are wonderful, and you have to decide which is best for you - personally, regardless of which is "more competitive" - who knows, you may not match in either....
Best of luck,
Airborne