^^^^ Agreed with this dude above.

Never store your tokens (or at least not all of them) in a place where you dont have full control of.
Even if the exchange has good feedbacks, positive reviews , top security and so on  - You still might loose your tokens or account even if its not the exchange's fault.
One day it can be hacked , or one day they even might decide to run to the bahamas with everybody's tokens.
You just never know what might happen.