Transparency1. PX72. M33. IO6The transparency level is adjustable on PX7. On high it works as it should and you can hear things around you, whereas on the IO6 it doesn’t make any noticeable difference unless you pause audio. It was decent enough on M3 but not adjustable.Controls1. IO62. PX7/M3They all use buttons instead of touch, which I prefer. As I wrote above, the play/pause button on the IO6 is large and easy to press. This is great on your head, but it also means that it is easy to accidentally hit play while in your hand or on a flat surface. On the IO6 and M3 it is a small button on the rim of the ear cup.The volume button are separate and use by hitting the top or bottom of the black ring around the Dali plate. This is much easier than feeling your way to the buttons on the rim of the IO6 and M3, for fear of hitting the wrong one.Ear detection (auto play/pause)1. PX72. IO6/M3PX7 has auto-pause/play with adjustable sensitivity and the normal setting works perfectly. It was not adjustable on M3 and was overly sensitive. It would be triggered by a turn of the head, so I deactivated it.IO6 lacks this feature and although the play/pause button is huge and easy to press (the coloured Dali plate on the ear cup), the sound if you temporary take them off your head will disturb people in quiet places.App1. PX72. M33. IO6PX7 has an app for settings and updates. It lacks an equaliser. The M3 app did not work in the month I had it. Its equaliser was overly simple. No app for IO6.Announcements1. PX72. M33. IO6* I turned off the M3 announcements from the app because they didn’t always help, especially battery life. IO6 announcements can’t be turned off and they are not perfectly clear because the same button runs the sequence of ANC and transparency, and at the end of the sequence it just says “off” and “on”. IO6 also announces battery level each time you turn it on. PX7 notifications felt just right and can also be turned off from the app.