I don't remember exactly, but I think there is only a difference in spreads. ECN account offers floating spreads and Fixed account fixed (obvi). There seems to be no more significant difference. Personally, I prefer an ECN account because it offers a bit lower spreads. But it seems that every trader should choose account individually, based on personal trading needs. In any case, it's a good thing that AAFX Trading gives its clients a choice between the account types, with slightly different trading conditions. Because I don't really like when there is no choice.