MysticSolarVirtually identical sound-wise. The K712 has a slightly tighter fit and finish, has orange-colored accents (with a sparkle-type sheen to the color), comes with a few more accessories, and cost more. Between the two, I'd take the K7XX every single time unless you can find the K712 for $200.
MassEDUK712 Pro is $260 on Ebay. I believe K712 Pro is made in Slovakia. The China made K7xx is about $40 less and will arrive my door next week. Hope the K7xx is really that good .
MysticSolarI owned both the K712 and the K7XX for almost a month before I sold the K712. I literally tried to hear a difference between the two "blindfolded" (my wife helped me several times with this) and I wouldn't bet a penny that I could call it right. To my ears they are identical. The K7XX, comfort wise, is identical too and both use the same ($100) memory foam earpads. Same headphone except the K712 includes a bag and a second cord and the K7XX is MUCH less expensive and hey! NINJA BLACK!
MysticSolarthese two headphones have the exact same driver and design. the only difference are where they are made and accessories included. unless you can find the k712pro for the price of k7xx, id go for the k7xx. Also, my k712 says made in Austria on the box, if that matters to you.