Cardio is cardio.
The most efficient way to burn fat is a good clean diet.
You can't target burn fat anyway, so why does it matter if you're rollerblading at 70% for 30 mins or walking at 70% for 30 mins? Your body just knows it's burning cals.
Personally, I like to alternate sprints with long 60 min moderate sessions because the sprints keep burning long after the sprinting stops ("cardio" stops when you stop, for the most part), and I get a solid anabolic response from it (as opposed to the catabolic response from long term stressful work).
I should attach the disclaimer that only do cardio when I have to (outside of fun stuff like biking with my son, long walks, hiking, etc...).