I started using the Step Mill about 4 weeks ago. 3 X per week for 25 minutes. HOLY SHIZNIT!!! I only do legs once per week (Leg Press, Leg Ext) but I swear my legs are growing like crazy from the Step Mill. Maybe they are just changing appearence but I could swear there is new growth. This is definitely my #1 choice for Cardio. Any other experiences with the Step Mill..I am very curious now that I see its potential.