Please, allow me to run this by you for comment and criticism.
After research, here's my envisioned setup for gaming on a PS4:
Astro Mixamp Pro 2013
I was considering the HD650 at one point, but decided against it because I believe the Mixamp won't drive the HD650 ($500) to its full potential, so there won't be a real difference with the HD598 that I can get in Canada for $260. I was drawn to the HD650 because it's more open, but I believe that I won't hear the difference in games. I also prefer the detachable cable of the HD598. Please, bash me if you think I'm wrong.