The U.S. Army and U.S. Marine Corps both have their advantages and disadvantages. Both organizations require very rigorous training and a career in both can see you deployed to a war zone. Both organizations also offer opportunities to serve your country.
The U.S. Army may present some distinct advantages over the Marine Corps, particularly its physical fitness criteria, organizational size and the quality of life of its soldiers.
Physical Fitness Criteria
The Marine Corps does not have a push-up test but it does have a pull-up test. Both the Army and the Marines will require you to complete 100 situps. The Marine Corps requires a certain time on a three-mile run; the Army requires a two-mile run. While the time-per-mile differences are negligible, you may find it easier to run 2 miles than 1.5 miles if you have more endurance than speed.
The Army is the largest branch of the U.S. military. This means it has more soldiers, more cooks, more helicopter pilots, more doctors, more lawyers and more of every other occupation than the other branches. The Marine Corps, on the other hand, is the smallest branch of the military, and is closely associated with the Navy, upon whom it depends on for doctors and lawyers.
What this means is that the Army has more career opportunities than the Marine Corps; more people means more jobs, which means it is easier to advance your career. On the other hand, for some the smaller size of the Marines and its reputation as an "elite" force is a point of pride.
Quality of Life
Finally, some would argue the Army offers a better quality of life. The Marines are generally among the first on the ground when the U.S. deploys forces overseas, though this certainly is not always the case. Because of their association with the Navy and traditional role as amphibious forces, Marines sometimes spend months and months at sea during peacetime as they often deploy on Navy ships.