A few months ago I did a comparison of spreads using IG, CMC, GFT, FXCM, Oanda and Go Markets. I found that some of them were better for some pairs and worse for others, but that overall there wasn't much to choose between them, except FXCM were a bit wider usually. They all vary the spreads at different times during the day, too, so it's virtually impossible to come up with a definitive statement as to who is best. FXCM say they offer fractional pips so that they can offer you 'even tighter spreads' but my observation was that they actually use them to widen the spreads. Like they would have the EURO at 2.4pips when others would have it at 2. On the other hand I have a friend who swears by FXCM for general all-round performance. Horses for courses, I guess.
Remember there are other factors than spread to consider, notably 'how safe is my money?' and how reliably you can trade at the screen price without slippage or requotes. I've just started with Go Markets because I like the MT4 platform and the money is held in a client account at the NAB. Execution seems good so far.
