I'm going to be purchasing new 15" Retina MacBook Pros for my wife and daughter in a sneaky attempt to prepare the grounds to justify a new Mac Pro for me in a couple months. Both gifts will be upgrades from their current late 2008 5,1 MacBook Pros. The wife should be plenty satisfied with the 2.2GHz model as her use is fairly light. The daughter wants as much processing power as she can get, but I think considering that she's not a gamer or a video editor, the 2.5GHz model should be fine, especially considering the speedy Flash drive, as well as the quad cores, RAM and GPU improvements over the last 6 years. Is there an appreciable difference between the 2.5 and 2.8 models?