Transaction from polo to rex is 1 day! In one day you could very colculate with price...
buy bitcoin, send to bittrex and buy emc2 there...no problem
At beggining was very different price POLO/REX, I was buy on POLO at 700 and then next day after 999 conf. sale at 1300...in the sam time was price on rex 1000-1100, 30%...