The only thing about the K712... It's at least like $130 more than the Q701, new. The sound is more refined and also easier on the ears, but by itself the change is too slight to justify the price difference from a Q701. For me, it's a keeper though due to the headband, comfort, I like the coiled cable to keep tidy at shorter distances, less fatigue when plugged straight into underpowered devices (iPhone, Mixamp) – it adds up, maybe a bit less than the price still BUT it saves me from having to mod and get amp-picky. It's the best AKG in my opinion, but won't change the world for Q701 owners.
Personally, that extra $130 for the K712 (or K702.65 in my case) over the Q701 was worth every penny to me. I tried the Q701 in the store and took it off in 1 minute it was so uncomfortable, due to both the bumpy headband and stiff ear pads. I looked for Q701 mods on head-fi and it would be $60 for the memory foam pads from the Annies and another $50-60 for the flat head-band from the K602 or something, plus shipping to Canada, plus modding time (since the headband replacement is NOT an easy process) and the $130 more for the K712/K702.65 is downright reasonable. Actually, the K712 is a better deal because it includes 2 cables, the standard long straight and shorter coiled. I ended up buying the AKG coiled cable for $40 for my Annies afterwards. If it K712 was within $40 of the Annies when I bought mine, I would have got the K712.
I definitely appreciate that you are helping me make an educated choice. The issue is that its either the X1+Boom Pro for $330 with no amp needed or the K712+Seperate mic+E12 for well over $500. Huge price difference there and I'm getting uneasy now that the price could be increasing rapidly. I'm using PS4 and Xbox 360 by the way.
Just to throw in another wrench into your decision making process, if you decide on the K712 and you don't need a portable amp, consider a desktop amp instead, like a Fiio E09K, JDS Labs O2, Schiit Magni or Vali, all of these are $100-130USD+shipping. Lithium ion batteries have a finite lifespan and when it dies, who knows whether the manufacturer still has a supply of replacements. If you go with an AC powered desktop amp, that is not a worry, except for maybe a faulty AC adapter (happened to my 1st Fiio E09k).
I'll re-iterate what others have said, you will need a powerful amp to drive the K712 properly. When I first got my K702 Annies (also from razordogaudio.com, for a tiny bit less than what you're looking at for the K712) I was driving them from a Fiio E17 and thought that sounded great upgrading from an ATH-AD700. Then I drove them from an Audioengine D1 (which was actually under-driving them even more than the E17), THEN I finally got a Fiio E09k and WOW... I didn't realize how good the Annies could sound, almost like a new pair of headphones. Then I got an Asgard 2 (upgrade-itus) and it was only marginally better than the E09k.
I'd say if you can afford the K712 complete setup without going into undue debt then go for it. It *should* reduce the temptation of you buying all the lesser headphones until you decide to buck up and upgrade to $1,000+ headphone territory.
If I was to do it over again now from my ATH-AD700, I would jump right to the K712 + E09K and call it a day. The K712/K702.65 Annies are super comfortable (compared to the head torture device that is the Q701). I would not consider the Philips X1 at all because of the non-replaceable ear pads and poor customer service/support (search head-fi for "fidelio L1 service"), and good luck trying to get even that crappy service in Canada. That and the boomier bass of the X1. I really like the more flat/neutral response curve of the Annies. I've heard stuff with a more U-shaped curves like ATH-M50, DT880 premium, M-80 and I don't like the boomy bass and sharp treble. The K712 has replaceable ear pads and comes with 2 cables (I bought an extra coiled cable for my Annies). If you need chat capability, add the V-moda BoomPro and Zombie_X's soon to be released adapter, which I'll probably get a couple of, one as a spare or a future AKG headphone. =P That should keep you set for years for music and gaming. I'm mostly music and PC gaming but I did try my Annies with a Turtle Beach ACU and XBox360 (from the TB PX5 set I bought before discovering head-fi) and it really, really needs an amp to make them sound good.