If you have the time to test any or all of them and compare them you should choose the one that does what you want it to. Unfortunately you often can't use many different programs enough, especially in a field that you are learning about. I would recommend using FreeMind or any one of the others as a baseline and once you have used it for a short while, test each of the others and see which you like best. If you are new to mind maps it won't matter which one you start with.
All the best,
Jay |