I doubt many of the HE400 owners have heard the relatively new and prohibitively expensive K702/65 (compared to the Q701 and older K702s), but if the new K702/65 is remotely similar to the old ones, I'd go for the HE400s everytime. They are just more musical, warm, and engaging to me. The bass is fantastic, which was always something I missed on the old K701 and Q701 I owned. However, I'm looking into the K702/65 as a compliment to the HE400, as I know it's better for gaming, which is a major importance to me (obviously), and should have better mids than the HE400. So basically a balanced headphone to compliment the more fun signature of the HE400.