Probably more because of the 770 & 990 in particular. I think a lot of people (including myself) like the powerful and well extended bass and sparkly highs of these headphones but the obvious trade-off is the recessed mids. I'm definitely interested in getting a closed Beyer that is a bit less recessed in the mids compared to my 770s. I've been looking into the 660 and it does look promising. Hopefully this Custom One Pro is a bit of an improvement in that regard but from that initial review its questionable. I'm looking forward to hearing more as more people get their hands on these.