Kucoin was one of the first exchanges I used, but didn't stick to it for whatever reason I can't remember and isn't too relevant at this point. These platforms aren't restaurants to leave a positive review like you'd do on Google Maps, usually the negative reviews derive from dissatisfied users. For instance, I had been using Binance and Bitstamp for quite a few years with zero complaints, but never bothered to write a positive review about them.

Check other exchanges' reviews as well, Binance has a crap score on Trustpilot as well.