HD650 stock is kinda of dark and muddy sounding, even out of a good amp such as Zana Deux. I found that there was too much mid bass bloat and not quite enough treble for my tastes. Doing the coin mod to the front foam, and removing the back foam piece and adding custom damping make them quite the force to be reckoned with, IMO.
The HD650 easily wins on positional cues and staging, as in how far away the instrument or sound is presented in the audio. It's there with the M1060 but you really have to focus as the nuances get lost in the wall of sound. Really it has to do with the excellent driver setup of the HD650 pointing right into your ear. Planars have better frequency extension in the bass but their downfall is the left-center-right presentation. It's a startling change coming from speakers. HD650 is much closer to my reference speakers and makes mixing easier for positional cues and putting instruments in the appropriate place. M1060 give a different perspective and can let you see inside the music in a different way, which can be nice but overall I prefer the modded HD650.