I am using three investment platforms these are Poloniex, Bittrex and Binance. However, my favorite is Binance because it has good candle stick graph so that I can monitor the trending so that I can have an idea on when is the best time to buy, sell or hold my investments. Also, some altcoins are not included in Poloniex and Bittrex. But some altcoins in Bittrex are not included in Poloniex or Binance so it is better to have different investment platforms so that all crypto currencies are all there.