I wouldn't pick XB1 solely for the launch lineup. It's a long-term decision. Ultimately XB1 and PS4 will have some great exclusive games over their lifetime. Dead Rising is a timed exclusive so PS4 will get it sometime 2014. Ryse seems like a one-time play through kind of game (the graphics look amazing though). So really it gets down to Killer Instinct and Project Spark. Killer Instinct was cool 20 years ago, how well it will transition to next gen remains unknown until you get the controller in your hands. Project Spark holds a lot of potential, if you're into that creation-style gameplay. Lots of other games have attempted that and only Sony titles Little Big Planet and Mod Nation Racers come to mind as having been successful at it. Remember "RPG Maker" or "Create"... neither did I until I googled them. So unless you're a die hard Killer Instinct fan, or you really want the next Halo, I would stick with the PS4. It's a good console at a fair price with lots of great games arriving day 1 like COD, BF4, KZ, WatchDogs, Assassins Creed, a slew of sports games, and some quirky indie titles to spice it up. Dead Rising 3 will come in 2014 after you've played through this years titles and perhaps Infamous Second Son early next year.
You made the right decision preordering the PS4. Now you're naturally having second thoughts, that's normal. $400 is a chunk of change to set down. It's worth reconsidering. Just don't jump ship because of the launch lineup.
Best of luck to you with your decision, and please don't get swayed by Sony or MS fanboys. Both consoles will get great games and at the end of the day that should make your decision a lot easier to rest with.
