Kraken - Good site for US traders

BTCC - Good site for US traders looking for futures and leverage trading. Great signup bonuses

Binance - Probably the best overall crypto trading site but doesnt allow US traders

Bybit - Great trading platform for perpetual trading. Great signup bonus

Bitget - A new upcoming and challenging platform. A lot of focus on copy trading

MEXC Global - Appreciated for high non-KYC withdrawal limits

Any site can fail for a numerous of reasons, self-custody is always the number one choice to store you cryptocurrencies.