There's no best exchange. But i agree the mentioned exchanges above at least you are insured (this is based on exchanges recent hack incidents such binance) that even a hacked incident happened your funds will stay there.
Past incidents where funds were reimbursed should not be taken as a means of insurance. The reason they were fine is because it was only a small-scale loss and there is no guarantee that the SAFU jar will be able to cover every losses if a large scale hack happens.
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The SAFU could be their marketing strategy only but the fact doesn't give true insurance to their customers.
Don't believe in SAFU and store your coins with them in a long run, though they're trusted the best thing is to withdraw your fund after your session in trading. Never leave your coins in an exchange for a long-term purpose or don't let your coins sleep in their wallet while you're comfortable that it's safe, there's no single centralized exchange that safe nowadays.
The best golden rule was always this "
Not your keys, Not your coins" we keep advice this to everyone and remind them of the correct storing of our valuable coins. The best example is that what happened to MtGox exchnage will happen again in random trusted crypto exchangers.