Bitfinex often has a leading price, or sometimes is LakeBTC step ahead, no matter, the key is that price gap usually is $10 between them and BTC-e.

Even BTC-e has a high deposit usd fee, but if we buy btc at btc-e and sell btc at bitfinex or lakebtc, we also can earn a tidy profit, much more btc per buy, much more profits per sell.

Even when you buy btc from Bitstamp, instead of BTC-e, there also $3 - $5 gap, and by use of both Bitstamp and LakeBTC are the ripple gateway, and a faster btc/usd arb via ripple.