£250-350 for the leaked 4.2TF specs.
£350-400 for 5TF.
Hopefully existing games will take advantage of the additional computational power, offering smoother and more consistent frame-rates in the games which don't perform too well on the PS4 or have unlocked frame-rates without requiring a patch, otherwise we'll have to depend on Neo patches and hope that the developers offer them for the current games that are available.