I received my red ZS6 yersteday, I do hear immediatly how great it is (without any burn in).
I use a stock cable without mic for ZS3, odered on ebay L-R=0.6 G=0.8 ohms
(I have the KZ silver plated cable, L-R-G=0.4 but the trebles do not need to shine more)
On my dap with CS4398 dac, for me the sound is better than the excellent ZSR I have too.
First, the voices are not recessed at all, (voices are slightly distant on the ZSR) then the trebles are not agressive on my ZSR, but they are softer on my ZS6 (did I received the "ZS6-ll" ? as I have the "new box" on the right, see above p.1876)
I like the bass, they don't show off, they go strong and deep when needed, a bit different than on the ZSR.
There is a lot of differences off character of the sound, if you have good electronics.
I believe that with this level of quality, the player counts a lot.
Then yes, it looks very beautifull, but cause it is made off anodized aluminium, the color is a fragile layer, you have to care not to scratch it one on the other, or with any metalic object like the player or a metalic plug. I will carry outside rather the ZSR that is made off plastic.