yes, my issue is a bull (or bear) trending market means that the average of exchange A - exchange B over time is non-zero, in other words the opportunities tend to be in the same direction. So I have to move the BTC and USD back around which is instant for the BTC but takes days for the USD.
Thats very true, the buy side will always be cheapest at MtGox. The sell side at the less liquid broker so you will always be transferring Fiat. Bitcoin can be automatically balanced by your bot if it tracks your bitcoin trading activity. The Fiat balance always requires manual rebalancing through your bank, if you have a buffer amount then its manageable to always have your bot running even if the fiat will take 2-3 days to arrive.
