Neither, all of the Alienware products are overpriced, and the PS4 will soon be considered outdated when the Xbox Scorpio releases at end of this year, which is said to have 980 Ti level graphics (6 TFLOPS).
I'd either wait until you can afford at least $600-$700 and build your own PC, or get the Scorpio when it comes out. The games you're talking about require a fair bit of power to run, and while the PS4 DOES run such titles, it would be at a dumbed down res and at 30 FPS, and likely dipping to lower than that in a lot of places.
And don't be fooled by building a PC, it's actually easier than operating and maintaining one. It only requires 7-8 parts, and there are easy to follow assembly and driver/OS install videos. Don't be fooled...