Unfortunately, at least for me, I don't really have glasses that would work hooked over the ear cups. Not an idea solution anyway. I think any over-ear headphones designed for mobile use should factor in glasses, so I again question whether or not ANC was a primary design feature of the IO-6. I can't shake the feeling the Dali headphone project started with the IO-4 and the IO-6 is the IO-4 with outsourced ANC tech tacked on. That said, I hear absolutely no difference glasses on/off. ANC on/off, sure. And I agree they are the most neutral and detailed, but I am not sure about natural. I reject the idea that neutral categorically equals good. But this is very much a preference question. I also wouldn't say the PX7 isn't detailed, I think they are.
Yesterday's IO-6 city test was disheartening in a way I didn't anticipate: It is parka season already where I'm currently based, and I like to wear my hood up. The IO-6 profile is much wider than the PX7, and the plastic ear cups rub against the hood making all kinds of scratching noises. The form of the PX7 prevents this, but so does mesh. Can't say thats a reason they put a soft fabric on the headband and cups, but it is a nice unforeseen benefit of this design decision. I think I'm taking the IO-6s back to the store today. I just don't have any real use case for them. The ear pad design is not great, lacks convenience features that I need while mobile, the ANC isn't anywhere near the PX7, and I do believe they sound anemic. A matter of taste, however.
IMHO, the PX7s are just so much better at what a wireless ANC headphone should do. And to me it sounds closer to what live rock and metal sounds like (the main things I listen to when I'm not listening to Kanye). These headphones are distinguished mostly by two very different approaches to headphone tuning. Neither objectively better or worse. I vastly prefer the B&W approach. If I keep the IO-6s, they'll suffer the same fate as my neutral IEMs that only get used at the gym. Actually, they'd suffer a worse fate, I'd probably never reach for them ever with the P9 and PX7 also within reach.
For those trying to decide between the IO-6 and PX7, there's no easy answer other than what your preferences and priorities are in this investment. I'm all but settled on the PX7, and all the IO-6 trials have done for me is reassure me that I've chosen correctly (for my ears and my needs from my mobile cans).