I didn't know PS4 was out for launch.
Anyway,the next gen consoles will need something VERY valuable to have any reason buying.Current consoles are as old as the oldest dinosaur ever found,but they are at least cheap
New consoles will
1) Either be 2-3 times more powerful,which is still much less powerful than PC,some of which are now 20 times more powerful than consoles.But they will be around 600€.So for the price of a PC,you get a console with less performance,and the only thing it does is play media
2) Or be very cheap,around 300-400 at launch,which means there will be a lot of sacrifices on quality and performance ,and you're better of getting a PC again,for just 200-300 extra
The only way i see them being successful (on a technical standpoint,because on sales they will be successful since many ignorant people will buy them) is having BOTH lower prices than the previous gen when it launched AND be at least 2-3 times more powerful.But that's kinda impossible