With similar configurations (aside from GTX765m for RE and GTX770m for RS), the price difference between these two models came up to about RM1.6k. I wish to have some opinions to justify the difference in cost!

Apart from the slightly better graphics card, backlit keyboard, dual fans (but not that much difference in temps?), and future upgradeability with the RS-15, is there anything else I should look out for?

Still in a big dilemma about which of these two I should pick 

Budget is definitely not the problem
But I'm not too sure whether it is worth the extra money for the RS-15/17 though
Of course, theoretically we would say the notebook will last long (say 6 years?) so we can upgrade in between to save costs.. Not saying Illegear is bad, but like all other brands, there are possibilities that notebooks will fail one... and what happens if it fails after the 3 years warranty period before I even got the chance to upgrade the GPU? The repairs might enable me to buy 2 "RE-15" already, one now, one 3 years later

Just saying la haha...  Money not easy to earn