I prefer HitBTC or OKEX. Okex with nearly 3 billion $ trade volume is the biggest exchange in this list, but also has fewer Coins overall (what is good).
Hitbtc is my personal favorite for beginner coins and with nearly 1 billion $ trade volume the second biggest exchange in the list, but has a ton of small coins (380+).
After all its preference, but try to look where the most INS tokens will be traded. That mostly means the most dynamic pricing