Get the ps4... $100 less expensive, better GPU, and it will eventually have the better library of exclusive games as the PS3 and PS2 did before it. Not to mention the whole "Kinect watches you to decide how to advertise to you" bit which is a bit.. wierd.
As far as last gen goes, the Xbox360 got off to a year head-start and had less complicated hardware for developers compared to PS3 - and had a few hit games like Halo and Gears of War, but the gaming community noticed how people stopped playing their 360s the last few years beyond the Call of Duty fanatics, whereas people are still buying PS3s and filling out their collections. By the end of the gen, there were a lot of 360s collecting dust, including my cousin's, which he basically hasn't even touched since he beat Bayonetta and Tales of Vesperia, which I had to buy for him (but really, for myself >_>
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As far as online goes, Microsoft's biggest edge was their paid servers vs Sony's free servers. Now Sony has gone with paid servers so it'll be similar, and I would expect PS to have bigger communities of serious gamers with less obnoxious 12-year olds.
Personally, I'm 100% sold on getting PS4 over Xbox One BUT I am no rush to buy a PS4 until I'm truly done with PS3 - still have to buy and play The Last of Us, Gran Turismo 6, The Witch and Hundred Knights, Tales of Symphonia HD, and a few others besides my backlog of owned. The biggest next gen titles - Metal Gear Solid 5 and Watchdogs, are also cross-gen games that we'll be able to play on our PS3s
As far as hardware goes, the PS4 is basically equivalent to my laptop which is kinda crappy, but I stopped caring about graphics after Uncharted 2 blew me away. One thing I do like about the PS4 is the new Dual Shock 4 - it was pretty nice when I played it at the store.