There are many options to choose from. Many comments featured Binance as the best platform for altcoins trading. I agree on it because I was using it for several years by myself, but in as much as Binance experienced a massive security breach on May, which resulted in a theft of 7,000 bitcoins (
https://cointelegraph.com/news/hackers-withdraw-7-000-bitcoins-in-binance-crypto-exchange-security-breach), I have some doubts about continuing using it. In general, centralized crypto exchanges are an undesirable place for storing your crypto funds, no matter how secure they are or how secure they claim to be. I think in this situation we can only rely on the platforms history. For instance, I use CEX:
https://cex.io/btc-eur, a crypto exchange that has never been hacked. This fact speaks for its reliability and enhanced security measures. The UI is intuitive and easily navigable, plus there is a mobile app for Android and IOS. As a bonus, in addition to the crypto trading, it supports fiat to crypto pairs.
Those exchanges you see that has not been hacked is not because of their strong security mate, it is just because the hackers has not focused on them or picked interest in them. You and I know how popular binance is, and if a hacker is to target any exchanges first, it is going to be binance because of its popularity and because they know they have lots of users and could guarantee that majority of them will be storing their coins on this exchange because of the trust they have in them.
It is unfortunate they succeeded, but I am sure they would have out lots of stronger security backing in place and you have nothing to worry about again, just dont keep your fund on any exchange.