If you are a stat guru iscore is the way to go. It gives you a lot more detailed information then game changer. You can do pitch location, errors throwing or fielding by position, a lot more in depth hitting. You can also broadcast your game live.
I have used iScore the past 4 years. I would highly recommend it over Game Changer if you/coach want every stat known. GC is user friendly; however, it charges to broadcast the game and does not give the option to break down the plays. Another thing to consider is what device you have. GC is still in beta phase with android.