Nice service for arbitrage traders. But we should consider the fees before jumping on the trade. You should probably indicate the withdrawal fees for each coin shown from the respective exchange. That way it will be more helpful.
Most exchanges actually charges a small fixed fee that shouldn't have bif impact over your profits.
The two big problems are actually:
Withdraw times. Some of those exchanges actually have pretty slow verification for withdraws. Like Poloniex, which may hold your coins for hours, while the price stabilizes oe gets worse on the other market.
Liquidity. Some markets may actually have a low liquidity, therefore the high difference in prices. This could make the price change a lot while you sell/buy. Making you even or worst.
