Hello, I am a first time Macbook user. I just ordered the 15" 8GB 256GB SS 2.4 i7 core with mountain lion OS. I do music production and some hobbyist photography and video. Main use is for music recording though. My big question is for $150 more I could have ordered the brand new version. But I stretched my budget to get the one I ordered. I would have loved it better with 512 GB but I do have a PC laptop loaded for assistance in these areas... Big question: is there a big difference between the latest and the one just before....should I cancel the order and just try to get the latest??? I'm trying to explain to my wife why I have purchased two very nice laptops in a week....... Any thoughts would be greatly appreciated.