Im now using directly and playing with the arbitrage on blockchain.info buying and selling ETH with BTC with their %. If you focus you could earn some $ as I do.
Arbitraging is a very difficult thing to do since many people are now using bots in order to find those opportunities and make money out of them and another issue with arbitraging is that you need a huge amount of money in order to make decent profits and that is something that not everyone has.