The arb is like a faucet, but the risk is greater, you will loss once the price balance.
You can potentially make a lot more money by using arbitrage then you can via a faucet, however the risk is much greater.
There is a reason why the market price is higher/lower on one particular exchange, and that reason is almost always going to be the fact that people are having difficulty withdrawing either fiat or bitcoin from the exchange
At present, which is the high liquidity exchange?
BTC-e? high fee
LakeBTC? Bitfinex? Too little funding channels
Certainly not Bitstamp anyway.