The CC routine I am using specifies two days per week with two exercises each day. I have expanded that to four days, with one exercise each day because I get impatient with so many days doing nothing. They are easily doable in 15 minutes. For example, today is pushups day, and I am doing them while I read and write on the forum here, so realistically, I am doing three sets of pushups in about three minutes. That's one of the nice things about bodyweight exercises--you can do them anytime, anywhere.
CC and and Primal Fitness are very similar. CC is wider in scope and much more comprehensive. With the training I got from CC, I am able to construct my own progressive exercise plan, tailoring it for my needs, preferences and goals. Primal Fitness does include sprinting, which I think is a very valuable addition.
If you have questions, feel free to ask, or post in the fitness forum. There are many people there able to help you out.