I personally use Binance and Yobit because of thst fact that both of these platforms are widely accepted by everyone. I once used Poliniex and I must say that it offers a great experience as well. If you want assurance, go for Binance and Yobit. 100% legit.
Yobit was not encouraged to choose a trading place because the risk was very high, and in the past there were many investors who lost money here, so be careful when choosing this exchange. I think it's best to choose trusted exchanges like Huobi or Binance because these are the best trading platforms at the moment. Also, the trading volume and liquidity here are always very high, so you will not have to worry much about not being able to sell.