Anyway, you would want it because the PS4 will be awesomerrrr.
Well, because the PS4 will be AWESOMER!
Honestly though, I will bank on titles being released for both systems for at least a year. I will buy a PS4 after the "Buggy" Systems have been picked up by those unwilling to wait it out.
While I know, any system is not completely free from bugs, I can say the track record, going back to the PS2 has been questionable for first year released systems.
Still, you know the graphics for a game you buy on the PS3 will be far better on the PS4 version. Just depends on how bad you want it.
some electronics I own like my phone I'm always 1 generation behind. I have the iphone 4 and wont upgrade to the 5 until the 6 comes out. Some things I'm fine w/ being one generation behind. When it comes to consoles thats not the case. I'll get the PS4 when it comes out. I'm not worried about buggy first released systems. Ive owned 2 nintendo systems and 3 sony systems ( the PS2 and PS3 at launch) and I have no problems with any system. If by some chance I did Id get another one under warranty. Being that the PS4 is so much like a PC I'm not to worried about it since the majority of them work fine out of the box.