Hi, I just bought a base 15" a week ago, so it's still in it's return period. I struggled to decide between 13 and 15, but settled on 15 for the higher RAM and processing power. I find that I only occasionally need the quad core when I do video encoding, and I have an external monitor. I'm just wondering if it's now worth getting the newer MPB 13" with updated Iris and processor instead and saving some money?