They both have their benefits. Hub motors tend to be a little easier to operate if you are a less experienced cyclist because they require less shifting of gears. Mid-drives tend to get a little better range for equivalent battery capacity because shifting will improve efficiency. While theoretically, you get better hill climbing with a mid-drive, you'll usually find both types will climb just about any hill. Check out Blog Post - COMPARISON OF HUB MOTORS VS MID DRIVE MOTORS for more details information.