Just for my 2 cents..
I read in one of Covert Baileys books that jumping rope, while a good cardiovascular exercise, is not a good exercise for the long run not only because it is extremely high impact, but also because, he states, that the nature of the movements are very easy for your body to get used to and adapt to. It is like that one repetetive movement..over and over... Good for improving your cardio but not so good as a endurance cardio exercise for fat loss..