The best thing about using a treadmill for incline is you get to adjust the incline. My advice would be take it to the highest percentage. You will get the most out of the exercise and also burn a lot of calories! When it becomes too difficult, try bringing down the speed instead of the incline.
If you are trying to lose weight, this is an excellent cardio workout. Easier than running, but incline walking can definitely be challenging. Your heart rate to be in the fat loss zone. Why this sheds pounds:
Incline walking is a cardio exercise that gets your heart rate going, and essentially that's all you need to burn calories.
Why this helps shape your booty:

Like I said before, I don't think this exercise is more efficient than stair stepping in shaping the glutes, but it is an easier, more low impact way to make a difference in your body. This also strength the hamstrings, which in my opinion, adds to the sex appeal of your body.
As with every exercise, you must give your body time to change!
