Love this concept. Comprehensive challenges push you to improve each day. My only complaint to date is the lack of true calendar integration. The app needs to do a better job of tracking what has been done "today" and what will be done "tomorrow." After completing a challenge the workout tracker automatically rolls to the next days workout but the attached calendar shows what should be on tap for tomorrow as due "today." It should say "tomorrow." Maybe if the app interfaced with the phones clock the workout could role-over at midnight. One could then see what is actually due today and better track if they are multiple days behind.
CI Guy about 30 Day Fitness Challenges