I've long since moved on to Level 2 of The 30-day Shred, and am definitely seeing results. My core is much stronger, as are my arms, and even my legs. My back hurts much less. I have been trying to work out every day, but have missed a few days here and there. Honestly, though, I feel that if I work out 5 times a week I still reap all the benefits cardiovascular and muscle-building benefits of The Shred. Psychologically I need the freedom to skip working out some days.
But, by and large, my greater commitment to exercising has been good for me--physically and emotionally. So I'm trying to keep it up.