Here's an interesting one I read:

Winning the console wars: Sony's not-so-secret weapon - Destructoid

saying that the real key to success may be PlayStation Plus, considering the massive content it bombards you with, and having that for a brand new machine would be kinda unprecedented.

I think whichever company releases that "Netflix for Games" type service, and does it really well out the gate, will be the must-buy system out the gate.