With such a topic so broad we truly try to cover the basics from all angles in this group. Nothing too big or too small. Nutrition is as significant if not more as exercise is to reaching your goals so learn all you can.
You can benefit from both ways of cardio. Usually slower pace for a longer period of time (say 45min-1hr) is ideal. You should aim to get at about 55-75% of your maximum heart rate. *to get this, subtract your age from 220 (this will be your maximum heart rate) and multiply that number by .55 and .75. Try to get in between these numbers* You should also try out something called HIIT (high intensity interval training)Do a search on fitbuddy at the bottom of this page to learn more about this type of training.