Honestly, I highly doubt the zs5 is better, but I never heard it - just saw the ridiculous pics and videos of the drivers covered in glue and drew my conclusions. Gone are the days I would by overhyped stuff to disprove the claims, so I'm not shelling out any money for zs5 or zs6 just to bash on them. I still keep my opinion that people are jumping on those cheap hybrids just because of the number of the drivers and the supposed tech advance even though there's close to zero R&D, zero crossovers etc. And there's zero hype for the single driver xduoo ep1, which I'm willing to bet good money destroys at least half of all those "giant slayers", coz it's a lowly single-driver iem from an "unknown" brand, while KZ is established "audiophile" trademark. And as far as the re400 goes, there are plenty of reviews, including joker's, so no need to promote it any more - as I said, it's not my favorite iem in the price range, but it is good nevertheless and there's no grain in the treble at all - can't hear any.