Just as the title says, but before the PC MASTER RACE or the Sony [censored] come to start a gang war in the reply section, there are a few things one needs to keep in mind.
First of all, I can only run Fallout 4 on medium to medium-high settings, however I have a gaming laptop that would allow me to carry the game around with me.
My laptop specs are:
Processor: Intel Core i7-5700HQ 2.70GHz
GPU: Nvidia GTX 950M
Ram: 8GB

Do you want the freeom to play it on the laptop more than "easiness" of not caring about specs on the PS4? You could buy both of course, but that depends on if you can afford that or not. My personal experience on having a game on two systems is though, that I play on one and not on the other, but that is as said, personal.