Think i'm gonna pick a pair if i see them on sale at a good price point, now they cost a lil bit out of my budget.I do recommand to you the ZSR. Night and day with the ZS3 (I have) considering medium and trebles details !
The bass are better than the ZS3, even more punchy and deep.
The voices are well present & detailed (even if on the ZS6 the level is higher)
The trebles are very detailed (On the ZS3, for me the trebles are weak with very few details. even with silver cable and foam removed)
I will try contacting uiisii to get a discounted sample maybe in exchange of a review here.They are not as contoured as the ZS3, more of a generic shape. Very comfortable to me, but everyone is different. There is only one way to find out.
Try foam tips : i had several problems with many iems (even zs3) like yours, and i can say that when u try foam tips, u never go back.just received my ZS5's ... I think they sound great, but how the hell does anyone get them to sit securely in their ears ?!!!
I'm using my usual sized spiral dot tips and they just keep popping out .
GRRRRR....
You lose a very little bit of bass but you're pleased to listen to your music as the in-ear fits perfectly and doesn't pop off.