Good exchange is exchange that operated more than 2 or 3 years and they has good reputation, never get any hack and comply with the regulation in the country their located. I used Bittrex and Poloniex more than 2 years and i have balance in that exchange also since 2 years and untill now that my balance is safe. So this both exchanges is one of the best exchanges.
If good exchange is that operated more than 2 to 3 years. How about Binance, okex, and houbi these 3 exchange as far as I know surpassed Bittrex and Poloniex already and these 3 exchange platform also listed on top 10 exchangers. Probably, in choosing a good exchange I think the good basis is the volume itself they have. Meaning, years is not a basis for us to know the good exchange.
Actually we have to depend on some factors that can help us to choose a good exchange. Time , experience, skill or that sorts of things is kind of necessary when choosing a suitable exchange. Combining these factors together is brutally helpful. First of all, we should put the security on the top one that is the most important factor. Because obviously if the exchange is not secured, your asset will not be guaranteed. Your guard should be up every time. Also, youd better build a wealth of knowledge in order that you can be much flexible when choosing exchange as well as making a decision suitably.