(honest opinion)
Ive been a/b testing my zishan z3 with my asus zb551kl phone (zenfone go 2017) for quite a considerable amount of time, (headphones used: kz zs3, bosshifi b8, isk hf2010, grado sr60e) not the most high-end cans but it does the job, but you know what, the difference is not far, literally you wont notice any difference if you just listen to it casually, the only slightly noticeable difference is the wholeness of the bass, soundstage is a little bit/microscopically wider on the z3, clarity wise theyre the same, with treble on my phone slightly better. i dont know the specific dac on my phone but the asus zenfone 2 have a hi-res dac (i forgot the name) maybe they use it still on their lower non-flagship smartphones. But if the people here in headfi notice a diffrence in sound quality in zishan z1 to z2 and zishan slightly better to walnuts, then i think my phone produces better quality than the z1 and walnuts (?) thats my only assumption though, im still using the z3 for only a few hours so maybe it will benefit from the burn in(?). For that, am I disappointed to the z3? kinda, i thought the difference is that big but unfortunately its too minuscle. but usablity wise it doesnt dissapoint its still a great dap/dac. but sound quality wise it feels to me like its more like a sidegrade than an upgrade, this also makes me question the hype over this daps, Or....maybe my ears are bad? but I dont think so, im still young and I only listen to music on a decent volume and time so definitely my hearing capabilities are still in good condition. just take this with a grain of salt, but this is honestly what im hearing right now.