I only trade at poloniex,the best currencies to trade are those with the biggest ammounts ,but you must look the chart and search about the fluctuation on them ,as eth has been pumped from 200k to the current value,soo expect a dump from no where,bts were on forbes this days and had been pumped since that.Yobit its a easy platafform to play but several no interest coins there soo you may fail into one and loose bitcoins too fast.