I upgraded from an AD700 to the Q701. I don't feel like I lost anything regarding spacial perception, but gained some bottom-end presence and a kind of liveliness. Going back to the AD700, audio sounded slightly more dull and tinny, but the headset was lighter and (since I'd perfected the shape of my AD700's headband) more comfortable on the skull. Granted, I have no comfort problems with the AKG since I started using a seatbelt wrap to cushion the headband bumps.
Overall, they're both good headphones, but I'm happier and more excited to listen to the AKGs. I've had them for about a year now, sold my AD700 about two months ago because I was hardly using them unless for comparison. If you do upgrade, you'll see... You'll just want to USE the AKGs more often
I haven't found an equivalent portable, probably never will by the nature of the beast.
Edit: Oh, gaming specifically, with headphone surround, I murder in competitive and happily get lost in single player. I am very happy gaming with these and a surround processor like Creative's sound cards or Turtle Beach's DSS dongles.Edited by Evshrug - 6/12/13 at 1:38pm