Don't go with PRO700MK2, it's anything but flat, Xone not so either, Denon best of the bunch but the little brother HP700 is actually better of them and is very flat with a slight midbass bump, highly recommended, besides the very slight bump in midbass the mids and highs are just very nicely balanced and flat all-round, couldn't hear any excessive peaks or dips. What's best is it also features a very nice soundstage. It's more on-ear than around ear though unless your ears are very small, I managed to get my ears fit inside with "
stretching of the pads" but the problem then was that the ears started touching the driver enclosure which caused discomfort as the pads themselves are too thin, you can fix this by applying some extra paddening underneath the pads though to make them deeper.