I'm contemplating getting the $1489 rMBP 15. Is it worth it to get it now, in the sense that it'll be competent by 2019-ish when I plan to upgrade to Cannonlake? It'll be used for schoolwork, Python, and general web use. It's the late-2013, with little difference to the 2014. Should I get the 2013, 2014, or hold out for Broadwell?