The unit I have is the older version of this, which has 4 "workouts" (basically the amount of time increases each level from 20 min to 40 min, and an intensity setting from 1-100. I have never had an issue with it not turning on, aside from when the batteries drained. It does go through battery power pretty quickly, which is one of the cons. I can't really remember the manual that came with mine, but I do not remember it being all that hard to follow. I use it three days a week, and I definitely notice my core being stronger, my posture getting better, and my abs are sore after each use.