As an owner of the AD700 (years before all the SR850 and FA-011 and other headphone hype came about; instead of spending $84, I could have just spent $50-65 with a bundled condenser mic and still have money left for better pads), I can comfortably say that it's exactly what everyone else says about it...well, except for the comparisons to other headphones I don't own. (I still might pick up some SR850s eventually, if only to verify the claims of their performance vs. AD700s and have a backup set in case anything happens to my Stax Lambda setup...and of course, a bundled C01 condenser mic for hardly any more than a standalone SR850.)
But as a gaming headphone, they're quite comfortable and perform well enough...if you're looking for competitive gaming performance and not an "immersive", "fun" sound with boomy bass. It's harder to EQ up than down due to clipping, so they suggest to get cans that are at least more balanced in frequency response and EQ the bass down if necessary. (The AD700 is certainly not balanced; if the bass being quieter wasn't bad enough to some listeners, the treble is noticeably louder, further accentuating the deficiency.)
There is much room for improvement on the music side of things, but if gaming is all you plan to do, I wouldn't spend much over the $120-150 mark, since that's well past the law of diminishing returns.