If they would be a shitty exchange then they would not try hard to get liquidity for new coin added by offering 1% to all XMR deposits and rewards for TOP traders. All that just show how serious they take their bushiness. And I am not worried there will be low volume. Most likely bithumb will be Monero second biggest volume exchange.
Bitthumb is currently the highest volume crypto exchange in the world
https://coinmarketcap.com/exchanges/volume/24-hour/(Ignore fake nonsense currently listed above it) EDIT: no longer there