There's not much difference between the two when it comes to weight loss. More reps will train more muscular endurance while fewer might garner a little more strength gain, but weight loss takes much more than just lifting weights.
Having any structured weight lifting program in general is important for weight loss, as the muscular recruitment it gives you will allow your body to metabolize more energy while in a resting state. However, you'll need to incorporate some sort of cardiovascular training or high intensity intervals to elevate your heart rate over and extended period of time in order to burn fat. Resistance training alone does not metabolize a very extensive amount of fat energy.