Sounds like the 2 are totally different animals. I'm really REALLY preferential toward JVC's Carbon Nanotube drivers and their amazing separation in the sound.
I'm looking forward to the MH1C and how everyone describes them as having such a smooth sound. But the only reason I'm not ordering another pair of FX40s is because I already have the HA-S500s. Otherwise I'd be getting more of that sweet sweet CNT action.