When it comes to any kind of cardio, all that matters is keeping your heart rate up for an extended period of time and doing it at the proper intensity level. It's pretty much personal choice when it comes to deciding what piece of equipment to use.
People ask me this question and I tell them, "The best piece of equipment is the one that you will use." So it doesn't matter if it's the bike, treadmill, stair climber, cross country skier, rower, running, etc. they all will do the same thing.
One tip though, cardio is boring, there's no getting around that because you are stuck on this machine for 20 to 30 minutes. But the one thing that gets me through it is music! Take a walkman or a portable CD player with you and listen to whatever kind of music you like when you're doing cardio. This distracts your mind so you are not thinking about the time you have left on the machine. As a result, this technique makes your cardio time go by much quicker!
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If you build it they will come