In my honest opinion they are the same in specs, no matter what people say they have on paper, in real life they behave exactly the same (as I've got to play on both consoles at different friend's houses).
If I were to buy a console I'd go for the PS4 though, just because I would like a change (I've had Xbox consoles so far - original , 360) .
But they are different if you try to compare a select few games side by side, though it's just minor details and won't look much different, unless you're the kind of guy who need to run everything perfectly. I say pick one that has more interesting exclusives for you.
I'm walking the nostalgia lane now, finished Bayonetta and Def Jam Fight for NY recently, one of the best fighting games I have ever played. Now I'm replaying Resistance trilogy on PS3 and Thrillville on PS2 to balance things out.