To me Both exchange are good if they both have good trading values and not using bot to manipulate the market thereby deceiving those new to trading.
I've use CoinTiger and I haven't had any problem with them, but I haven't tried Bilaxy exchange
This is why I prefer Dex exchange, no bot manipulation, no fake trading volumes.
To know good exchange, I think one should Start by testing the support team response time and how effective they are