I think it pretty safe to assume that there'll be a greater than $100 difference. If PS4S is $300 still, Neo will maybe be upwards of $450 to cash in on the more hard-core enthusiast. There'll be enough of a price difference to justify PS4S existence, that's for sure.
Furthermore, $100 is still a 33% difference. That's significant to a lot of the cost-sensitive.
I find it interesting "cost-sensitive" only comes up with regards to hardware... I'm assuming you weren't one of the ones on here arguing in favor of 4K blu-ray support even though those movies cost like $30 each...?