+1 on resistance training over cardio- a good circuit training workout keeps your heart rate up like cardio AND builds muscle.
Other than that, many articles I've read recently tout that shorter/harder workouts have better cardio benefits over longer/easier workouts. But I'd say do the one you like best, because that's the one you'll stick with anyway. Both will give you health benefits.
"A mistake is not failure but feedback. -Rod Gilbert"
It depends on your time. Technically, you can get similar results with both, it just depends on how much time you have to commit.
For example, on days that I have the evening off I much prefer to go for a 2 hours walk/hike around the river in my city than to spend 45 minutes on a stairmaster.
So long + moderate = short + intense is the short answer. Do what works best for you.
Technically, both activities have similar effects: burned calories (~500 range) and worked muscles (walking for 2 hours makes you just as stiff as being on the stair master for less than half that time)