Forex Robots, whose strategy allows longer time for trading, do not show a significant difference between the results of the live and the demo accounts. Such robots are, for example, the WallStreet and the Leo Trader Pro.
The Million Dollar Pips has however a significant difference between the results of the demo and the live accounts, because its strategy is to trade quickly, almost always within a minute. On the demo account, this can be carried out fast, because it does not need to find a trading partner, it only has to calculate with the current price on site. On the live account, the broker needs time to ask for bids from the partner banks and then actually carry out the trade, etc. In the meantime the price may change to the wrong direction, which worsens the results.