Interesting Question.
From the research that I've seen, multiple bouts of short duration cardio is equally effective as a single session of long duration cardio @ improving your Cardiorespiratory fitness. Assuming the total time for both is equal, with similar, low intensities. ( 3x10min = 1x30min).
Your best bet is to mix it up. Some days do shorter duration high intensity, some days do longer duration lower intensity. Just like you periodize you resistance work, you should do the same with your cardio. Variation will also keep you engaged in the workout and eliminate boredom.
Having said that, your specific goals need to be considered, when planning your cardio work.