Two subscriptions - want to alternate between platforms (PS4 - PC)

[Niwashi]

One more point: On the PS4 your SE account will be linked to your PSN account, so you'll each need separate PSN accounts as well if you don't have that set up already. (It's ok for one PSN account to be a sub-account of the other if you want. And it only requires the free PSN account, not PlayStation Plus. So there's no extra expense here - just perhaps a little extra setup.)

[Dark_Legacy]

Two more details nobody above mentioned yet:

1. You can get VERY cheap PS3 boxed version of the game instead of PS4 one (in UK already lesss than £3) and then upgrade it for free to PS4 version (before ned of this year). As a benefit of doing that you can then play game on PS4 without having disc in PS4.

I just wanted to add one more important piece of information to this post. While this does work and saves you money on getting the ps4 version. The PS3 version can only be registered to your account on a PS3 so make sure you have access to one before you do this as I thought I could just register mine online and was surprised when it prompted me to register through the PS3 luckily I still had mine.