I believe that to be true...more muscle=more fat burned,but in saying that,I do think you still need a certain amount of cardio for good heart health...
When I was at the gym,I did a split..cardio,then weights,then cardio..but I didnt overdo the cardio,like spend 45 mins on a treadmill..because I felt I was just wasting energy that could be used in weight training..
I only did light cardio to warm up and cool down...