Its similar to your thoughts of the T2 being technically better than the ZS10. Its highly subjective.
The T2 plays very well on almost any source, sounds very good straight out of any typical headphone jack. But it can be mildly sibilant on some tracks.
The ZS10 needs a little bit of amping to get the best out of its drivers, sibilance is almost non-existent on the same tracks. If I can pick out sibilance on it, usually I can also pick it out on my HD6xx, meaning that its the musical track that has issues.
Its NOT impressive out of most headphone jacks though.
Though sensitivity levels are supposedly similar between the T2 and ZS10.
Its also heavily dependent on the sources you're listening to. Like say if you listen to female vocals that have been heavily processed( a few tracks in the Adele 25 album for example), you're more likely to pick up the sibilance. But if you were listening to audiophile vocals that emphasise on the purity of recording, chances are the sibilance will not be noticeable, if at all.
For that matter, there are some who listen purely to instrumental music of multiple genres, for those folks, sibilance for 99.9% of the time will not be an apparent issue.
Which is why some people still love the ZS6, even though its heavily sibilant. But on purely instrumental stuff, they generally sound wonderful.
