Nothing quite challenges the body like combat moves followed by exercises. This activates the body's front and back kinetic chains, creates a mechanical and metabolic load for the muscles to deal with and challenges the body's cardiovascular and aerobic systems. 3-Minute Warrior is a total body workout that isn't suitable for beginners but that doesn't mean it shouldn't be on your horizon. Everyone else should be looking at EC as a requirement.
Extra Credit: 1 minute rest between sets.