My only real complaint about them after 3 days of extensive listening is the amount of bass... It's too much to be called neutral. K712 Pro sound very enjoyable with metal, some rock and overly bright music in general. And yeah, I still find them versatile and quite balanced. But going from HD800, these are definitely nowhere as precise and monitor-like.
Too much bass in front of me - they just fail to deliver realistic bass guitar, properly imaged in front of me... They rather emanate bass all over the place which prevents other instruments to shine fully. Not as veiled as HD650 and definitely much faster but still, they are far from clarity offered by HD800s.
I'm not sure it's useful to continually compare the K712's with the HD800's, which cost 3 times as much.
I'll have to disagree with you on the bass issue; I think the bass on the K712 is very much in the neutral range.