$400 for what you're getting is cheap if you have the means and very reasonable if you have to scrape together every time you buy a new console. Sony engineers packed quite a bit of power into a modestly priced box.
Since there's a fair amount of overlap for 3rd party games (AC, Battlefield, CoD, Tomb Raider, etc.) the same $60 one would spend on a PS3 or XB360 version looks sharper, runs smoother and in some instances, has extra features. I won't say multi-gen ports are the reason to buy a PS4, but personally, if I'm spending $60 on a game, I'd like to pay for the better version. And no, I don't particularly care for gaming on my workstation, so the PC argument is out.