Samsung Z4 is a recently launched phone which is not an android phone. It is based on the Samsung’s own made Tizen OS. The tizen os is good if you get used to it but to my experience the phone is very bad.
I recently thought of buying this phone for my mother so I went to a nearby samsung store. So when I came across this phone it was a 4.5 inch phone with ips lcd screen not even hd. I know at the price of around 6000 you cannot expect much but I was stunned by the fact that when I started operating the phone on display at the store the phone was already hanging and lagging very much. On asking the representative about the lagging he said that there are many apps installed on the phone due to which it is lagging. But when I checked the the phone the phone did not have any third party app.
Obviously the seller wanted to sell the phone at all cost so he said that. The phone actually has very mediocre specs due to which it was hanging.
So if you are planning to buy this phone please consider other options as they will give better specs at the same price. Also as the phone is tizen based you will not find much apps to support it. Its better to find other android smartphone like xiomi, lava etc. Although they are not that famous like Samsung but they will still provide better experience.