I was only planning on buying a PS4 when I had the (false) assumption that they were going to fully support backwards compatability and let me run PS3 discs on it (basically when the PS3 had first came out, I had already decided to never get it because I predicted the next console to come after would be likely to play all those games anyhow). Since they feared it would allow Gamestop to cut far too deeply into their online "virtual console" sales, now I have zero interest in getting a Ps4.
They still have the physical capability to read and run PS3 discs, but the only way to actually access that functionality now is if someone was able to hack the console and release some kind of unwarranted software patch. I don't have a PS3 or any PS3 games, so I COULD just buy their console titles online and stream them, but my internet is barely at the threshold for being fast enough for that to work.
It was basically the deciding factor for me because the PS3 is where all the already released games are at, and would have given me a chance to have lots of cheap things to play waiting for new PS4 games to come out. I have no desire for paying full price for those titles since I'd only be capable of playing SOMETIMES (as in I could only play them whenever my internet connection does not hate me). The current lineup of PS4 titles is pretty decent for such a new console, but nothing really sticks out as "me wanting to buy a high-end console" for.
So as far as my advice goes, if you don't already have a good reason to get a PS4, or you don't already have in mind that "must play" game that you can ONLY get on the newest console, then you are much better off not looking for a reason to waste money on it. If I were to get one, it'd only be because Titanfall has inevitably ditched its "xbox exclusive" status. But even if it never had, it wouldn't have been enough to make me get a Xbox1, so it's not enough to make me want a PS4. (then again, nothing short of "the version of Spore we were all expecting before EA ruined everything" would have been enough to make me think I could actually WANT an Xbox1)
Maybe my mind will change on that by the time Destiny comes out, but its far more likely that I'll have already bought a PS3 by then, and I'll have far too many cheap, disposable, JRPG timesinks to play through to ever be bothered.