I’ve had the three and still have the IO6 and the PX7, to me the IO6 simply has much better sound, not just a little better but night and day better. I also find the Dali’s to be the most comfortable of the three, the PX7’s and the M3’s fall of my head while leaning back, and that’s no matter how tight the headband is adjusted. The PX7’s are the better cans to travel with, I find the ANC on these to be very good, they do however have a major problem with outside wind noise, so if its walking outside or commuting through a city and even if it is only slightly windy, the PX7,s are useless. If I could only have one pair and with my current lifestyle, I’d choose the iO6’s.