It's not necessarily an issue of which one causes more weight/fat loss. Of the studies I've read, both low and high intensity exercise has been found to be effective for weight loss and health/fitness improvement. The big difference is that intense workouts achieve the same effects in less time.
For instance, in the Tabata study, they found that subjects made similar fitness gains with 5 days of short duration high intensity interval training and one day of steady state training, as subjects did doing steady state training 6 days a week. The substantial difference was that the high intensity interval training took less than half as much time per day. (It also provided greater increase in anaerobic capacity).
So really, which type of training you choose depends more on personal preference, specific goals, and your time constraints. If you enjoy an easier pace and don't mind working out longer, do that. If you like short and sweet, make sure it's also intense. Alternately, do some of both and you get the best of both worlds.
ETA: SparkPeople has an article up about this: www.sparkpeople.com/resource/fitness_artic
Edited by: LEHERSELF at: 12/2/2011 (14:35)