Just received the AP3 and I am genuinely impressed. The sound is so deep, full and detailed that I could not believe it's coming from so small units just hanging on the outer part of your ear. You can really wear them for ever without feeling you have something in your ear. No pressure, no silicon, no pads, no weight. Surely city noises may cause the well known auditory masking, but on the other hand the open nature of the AP3 offers a new quality in the sound perception. You feel that sound is not produced within your head but around you, coming from outside. Yes, I believe it is a more natural way to listen, by allowing your ears to breath without blocking them, even with the "negative" effect of listening in parallel many different sources. I think that even music gets a new meaning this way. Also due to the lack of any seal, in combination with the adaptive eq, the bass as well as rest frequencies remain always fully consistent. As much as you may move, frequency response remains always intact. To me at least, all in ears including the APP, lose their seal after some time, which as a result causes the annoying weakening of low frequencies to the right or left ear. Nothing like that can possibly happen with the AP3 since there is no seal, thus they produce the same-stable response by just sitting on your outer ear, however your head may move. Ear is not feeling pushed so it does not fight to kick anything out of it. At the bottom line, yes I miss ANC when walking in a noisy city but it is a more natural and open way to listen to music. The bass is really impressive for an open earbud with zero seal, much better I think than on the APP. Finally I realised that with ANC or transparency on, which is how I was only using the APP, I never possibly allowed adaptive eq to operate. So it may indeed cause some differences in the audio quality.