I just did Level 1 for the first time yesterday - WOW. I really didn't think it would be that difficult but I was sweating and cursing Jillian by the end. The only issue I have with it is that I feel that the dumbbell exercises require a different weight for each exercise - doing curls with 3lbs isn't really a workout for me, but I can't do shoulder presses with 10lbs, etc. Not a big deal, I just kept all of my dumbbells nearby and picked up the ones I thought were most appropriate for each set. I'm not planning on doing this daily, but I will add it to my rotation (which includes a longer, more thorough weight routine and yoga). I also bought her "No More Trouble Zones" video, but after the Shred, I'm a little scared - NMTZ is over 40 mins!