Ha ha, nice.
For me, I'd have to say PS4 is the worst, at least for now. Things could change, but for the time being it does not have any exclusive games that I want, and very few multi-platform games, even. I don't see myself ever buying one.
Meanwhile, I don't own a PS3, but I might get one. Its library doesn't look as good as PS2 or even 1, but it's racked up a decent number of games that I think I'd like. I still don't want to pay very much for one, though: I got a PS2 back in 2011 for $30, and that sounds about what I'd want to get a PS3 for. Might settle for $50 if I have to.
That said, I've always felt the PS3 seemed like a better system than the Xbox 360. I like its controller better for one, and also, it had free online.