Alright I literally just read every post in this thread start to finish, as I am currently jumping into the deep end of proper audio equipment.
I have a few questions that I also posted in
Mad's thread
I have decided on getting a set of AKG K712s for competitive gaming.
What, these?
Dude! They're awesome! Yeah for media and casual games too!
The DSS is a huge value. The volume/voltage is more than enough, though it doesn't have the current and clean smoothness of the X7 it's still the unit that least needs an extra amp (the K712 is also more forgiving of hot treble in this regard than the Q701). If you have a DSS now, well the X7 isn't a limited time deal, and your ears & brain literally take time to train what you get from higher-end gear. I'd call the X7 a level 2 (or final boss, on hard mode with the extended ending, but maybe not the final boss on nightmare mode with the same ending as hard mode, if you understand the metaphor) gear, unless you need the convenience features, you don't have to jump into the X7 right away to have a great gaming experience. At this price point, and if your two consoles are right next to eachother, I'd say leave the USB plugged into the PS4 and just switch which console the optical cable is plugged in.
Now, the thing about the X7 and DSS is that it only comes with one built-in optical port. No big deal if you don't care about surround for one of the consoles (there is so much game overlap for the two current gen consoles!), you can use a cheap optical-to-stereo-RCA DAC like FiiO's D03k or D5 and plug into the RCA line-in of the X7. If you want surround, optical connection for both, you might consider getting
an optical switcher so you can leave both consoles plugged in.
Another option, near the same price but not as great for headphones in amping or headphone surround DSP, is a home theater receiver. Multiple HDMI inputs, remote, usually amping for 5.1 or 7.1 passive speaker setup, this would be a good choice if you have the space and intend to use speakers more than headphones. Like, you have a house rather than dorm, apartment, or condo. If that's your plan like 5 years down the road, well, by then receiver tech will have lots more doo-dads and functions. I live in a pretty decent-sized condo with three floors, and I have the receiver dedicated in the basement... and I almost never use it. YMMV.