Nobody knows the answer to this question.

There are some who vouch for x or tell y is better but nobody here, absolutely nobody knows their financial status, nobody knows how deep in debt or how many reserve funds they have, nobody knows the level of security they have or how bad or inexistent those are in reality.

All you're going to get ar the name of the largest and most known and that's it because something if this exchange has lasted for 4 years then it's trustworthy which can' be more false. If I were to ask what makes Binance or Huobi so secure the only answer will be that they have money and CZ said funds are safu, nobody knows the true situation as they don't have access to that data.

So bottom line, you're going to have to gamble on this and maybe in one year see that all top ]3 exchanges have been hacked while some no-name ranked 300th is still up and running.