That kind of pricing makes sense.
I can't say if it's better than the 681EVO because I've never listened to that model (just held it), but I can say with certainty that this is a better-built model, and far better-looking than anything they've ever released.
With that being said, the HD685, to me, is a pleasant sounding headphone, though it's difficult for me to gauge where it sits on the totem pole because I'm not usually a headphone user (mostly IEMs) so my experience with closed-back headphones is limited. Of the closed back headphones that I've recently auditioned, I don't think it quite matches the M50x in SQ, but it does come close. It's a more musical-sounding headphone at the very least. Again, I prefer sound signatures such as those of the NAD HP50 and Focal Spirit Classic, so YMMV.