As far as backwards compatibility I've read a few places that PS4 will NOT be BC. Which I think is a bad move on their case, but I'm more of an Xbox guy myself. I can't say I wasn't really impressed when I watched a Killzone demo on YT the other day. It looks really nice! I do wish they updated the controller a bit more, one of the biggest reasons I shy'd away from PS3 is the controller design is so awkward for me, though I know this is personal preference. I'm anxious to hear about what Microsoft has planned, I've heard they're a month out from releasing info! 
Anybody feel free to add me on Xbox Live, Gamertag: xsithlife
Anybody feel free to add me on Xbox Live, Gamertag: xsithlife