Just finished the program and it was... aight. I liked the variety but when it came down to it; all crunches or planks. Variations that may or may not target specific areas of a small group of muscles. That's just my opinion. You try it and finish it before you try blast me. There were a few times when I felt like complicated moves were unnecessary and I couldn't feel any difference in the movement or muscle or effort from say the standard crunch or plank. I would've liked a more consistent workout. I like balance and symmetry in my workouts as well so doing an exercise only once and never revisiting it made me obsess a little. I do feel stronger. My core is tight as a barrel. Definite improvement in ability. The last exercise of the program is max rep crunches. I surprised myself. Also 2 minutes planks were unreal to me but now holding a 1.5 minutes is hard but doable. 2 minutes plank is now on the goal list. I would recommend this workout but you're not gonna get a 6 pack in 3 weeks so do go in thinking that. Push yourself to keep up. Don't slack. You come out the other end with a stronger core. Also study the workouts before you start it. It's easy to get lost on the mix of styles and variations. Plus you lose a few reps if you don't know what is next and have to stop to look. One time I was like wtf? Crunch what? Good luck.