After listening for a couple of hours, i will agree with the following;
1. Source is very important.. somehow seems too warm and unclear mid if quality is compromised. In short it's a bit of hit or miss. For e.g,. if you listen through your mobile phone on mp3 or spotify it may not suit you.
2. The fit... first class design of the housing ensures it stays and seal perfectly into your ears.. need to try to believe.
3. the 2 pins are pretty thin so must be easy when plug in to the housing.
4. If you listen side by side with ATE, it's immediately very clear that ATE focus more on vocals while the ZS3 emphasies more on the bass and more colored. For critical listening ATE is definitely the choice.
what i am more curious is what custom cable will improve the sound.. i know there are tonns available but they definitely add up to the cost of having a very affordable piece of IEM.. is it worth the 'upgrade'.
1. Source and mids - I am also having this impression. I've been using them with a Sansa Clip Zip for an hour, now I changed to the Fiio X3II, same track, same format, and the mids seem to have opened a little bit.
2. The housings do look interesting, but they seem to be a possible approach to a custom IEM design, with all thoses curves and the way they are expected to fit in one's ears. Well, I don't have a problem with the seal (after some tip-rolling, opted for large silicone tips that came from my Xiaomi hybrids). But they just don't feel right. They don't hurt, but I think that my ear is not aligned with those weird forms. I tend to rotate it a little bit clockwise (reference to right ear) so that it sits perfectly in the cavity, but that long thinghy at the bottom levers it the other way. I end up with the cable sitting somewhat far from the ear contour. Maybe with a picture you'll get what I'm talking about. Jeez, I'll have to trim those hairs...
4.Comparing to the ATE, the ZS3 sound more "lively", more bassy, but with a less muddy bass than the ATE's. I wouldn't say these are "basshead" IEMs, but they have quite a punch.
With good source and files, I'm enjoying these pretty much.
Meanwhile, I tested them with the same songs in my Nokia Lumia 925... comming from Fiio to the smartphone, the mids do really suffer. and the general impression is that everything gets somewhat messy and congested. I guess the ZS3 needs some amount of power to behave well. I would not recommend it to use with your regular smartphone or little chinese DAP. Go for your amps and big DAPs!
(album used for this small impression: Sufjan Stevens - Greetings from Michigan , FLAC).