Also depends on what your goals are. For me I want to put on muscle and burn a little body fat so I NEVER cardio on empty stomach as that uses energy from muscle not fat. To burn my fat I need to do short intense bursts of cardio and intense progressive weight training. Intense weights will burn tonnes of calories and fat to reveal good growing muscle underneath.
If not focussing on building muscle but losing weight, I guess the reverse is applicable. Long periods of moderate cardio and long reps of light weights. but then I am just a punter, not expert. Just what I picked up along the way.