Every system has always been defined by its exclusives...GoldenEye and Ocarina of Time on 64; Halo on the original Xbox; Final Fantasy, Metal Gear, and God of War on PS2; Halo and Gears of War on 360 (and some great Arcade Games); Uncharted, Heavy Rain, Last of Us on PS3.
This next generation people can whine all they want about pricing and DRM, but the winner of this upcoming generation will be determined as the winner always has: WHO HAS THE BEST EXCLUSIVE GAMES!
Judging from their currently announced exclusives, it is clear the Microsoft knows this. Their list of exclusives crushes the ones currently set for the PS4. Things could change, but if they don't, that $100 price difference isn't going to mean all that much in the end.
What matters is Games, Games, Games. Right now, the Xbox One has them, and the PS4 just doesn't.
Disclaimer: I'm rich and have already preordered both systems.