If you know what you are doing, margin trading can be very profitable. The problem is the Poloniex lag scam along with the other scams they are currently running. The other day, I sold burst coins and then POOF my whole balance disappeared. 2 days later they gave me burstcoins instead of BTC and burst had lost 40% of it's value. They stole .13 BTC from me. If Poloniex didn't do insider trading and run intricate scams, it would be a good place to trade. I am done with them since they keep stealing money from me. Last week they charged me for lending when I had no orders open! And just stole 1/5% of my bankroll!