I'm thinking to buy MGXA2LL/A (Base model of 15" Macbook Pro with quad core 2.2 cpu) since there are good discounts. I can also buy the new 13" for the same price. I am using R software for some statistical computing in bioinformatics area for my PhD study. Which model I should take? Is there anybody using R statistical software with Macbook Pro 15" 2014? It has I7-4770HQ CPU while 13" model has I5-5257U CPU with clock speeds 2.2 and 2.7 respectively. Does 13" model gives better performance than 15" model because of its higher single core speed? I should buy the computer tomorrow. So your advices are very important for me.