Zen is better than White in terms of rewards. It is a balanced card. White is good for nothing except looks.
We get only milestone rewards that too after spending whopping ₹2lacs. Even that is mere 1%. Why would someone pay ₹3k for 1% rewards?!
All in all, Zen is better if you really want a Kotak card.
However they all are useless just like ICICI cards.