OK, so from Mt.Gox USD to BTC-e
aurumXchange charge 4.00%
BitInstant charge 3.99%
Some quick calculations for reference
110 - 105.60
120 - 115.20
130 - 124.80
140 - 134.40
150 - 144.00
I've noticed there doesn't seem to be as large a gap between Mt.Gox and BTC-e of late, so unless the fees come down there is now little use in this service.
Most likely the gap is closed
because of arbitrage and services such as ours or aurumXchange. Arbitrage generates profit essentially by feeding on the difference.