I have done this at a few site market that selling and buying bitcoin.But unfotunately is not really profitable.This is because don have a large amount of bitcoin.I lose with other competitor who have more large amount of margin.
But I had some profitable experiences with my arbitrage. When CLAM coins were trading around 0.006 btc, I did find gaps in price levels across poloniex and yacuna exchanges. I got arbitrage trading opportunities weekly two or three time some profit levels around 0.001 to 0.003 btc. I believe for the time I did spent, these must be a good profits.