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.
that is the problem with this kind of arbitrage trading between exchanges using altcoins: the profit is too little.
and when it comes to smaller altcoins the situation gets worse since they have a bigger spread and nobody trades them. and on top of that the orderbooks are too thin which means you can only buy and sell small amounts sometimes even smaller than the minimum allowed trade size!