This is really a personal preference. Treadmills tend to pull the ground beneath you, moving you forwards with less friction which makes running a bit easier. You can control your intensity, speed, monitor your distance, and modify incline at will. You’ll also find treadmills in climate controlled areas which are very much welcomed in the summer months of North Carolina. However, nothing beats fresh air and a change of scenery, visually seeing the miles pass by is very motivating. Our friends at Body Shot Fitness wrote a nice article on how treadmill miles compare to outdoor miles. You can check it out here.