Great music!
To my ears BA timbre "works" nicely (since the moment I got 1 More Triple that I still cherish), especially for string music and most orchestral.
More to the contrary, many/most DDs do not sound great to me due to their perceived droniness/tubiness (There is a point of view that due to omnipresence of DD in reproduction devices, strong preference to the "DD sound" gets imprinted).
Not to digress further, AS16 pro is great. AS24 is definitely a good upgrade along these lines, but at about 2.5 times the price - more for dedicated all-AB affictionados.
I tried to attempt a KZ hybrid comparison in the last few days, but digressed to all-BAs and blue cables
Anyhow, ZAT to me is very much at par with 1 More Penta and Phoenixcall.
The bass of ZAT, while mighty, does not feel tubby to me, compared to that of Penta. Bass of Phoenixcall feels the tightest and best integrated with BAs&SPDs - and I Iearned to appreciate this tuning with its lower pinna gain slowly but surely.
My problem with ZAT is that it is too bassy for me, I have to use extreme switch positions (all bass off, all treble on), and still I would possibly dial off bass a bit. Then, again only quantity is a bit too much, quality is good to my ears.
So if Castor bass/treble balance feels right, ZAT can be a mighty upgrade (is it worth 5+ times more is for each to decide).
I hope KZ will make "more Harman/lean" version of ZAT one day.