Hopefully a straightforward question, but you never know do you! OK, I have an early 2009 17" MBP 2.93GHz C2D and the most taxing thing I do on it is to run Lightroom CC to develop my Fuji RAW files. It's slow for this purpose and also struggles to maintain a synchronised Airplay stream to two devices at once. It's the processor as the 8GB Ram is never taxed. For other stuff it's absolutely fine. I don't video edit but do play back 1080p at 60fps from my cameras...which is also stuttery My choice is a fully loaded 13" with a Dell 4K monitor, which I would probably take away more with me for weekends and holidays...or a fully loaded 15" on its own, which is only 500g more but obviously not quite as portable. Portability is not a deal breaker, but how it performs in 3-5 years time most definitely is! I can wait for a June or even an October upgrade for the 15" What would you do?