Disclaimer: I run an exchange To do arbitrage, you need need the ability to move both BTC and USD between MtGox and BTC-E quickly. BTC is moved easily, at 6 co

Disclaimer: I run an exchange To do arbitrage, you need need the ability to move both BTC and USD between MtGox and BTC-E quickly. BTC is moved easily, at 6 confirmations (~1 hour) However, people are waiting up to 7 weeks to have their USD withdrawn (see Bitcointalk). Combined with lawsuits aimed at MtGox and lack of transparency, this leads to a situation where USD on MtGox is worth less than USD on BTC-E (or Bitstamp)