Nice thorough reply by FXCM. They have had a bad rep over the years but I've used them on and off and have never had any problems. Good for US traders too
I think there individual threads for most of the major brokers. The comments are generally mixed. I don't think you really know for sure how good a broker is until you use them
A back testing an EA that you don't know anything about doesn't make sense. Sure you can get great backtest results if the EA is optimised to perform well on the old historical data. The problem is how the EA will perform on new price information from a live market
You've got to use at least two brokers. Sometimes one goes down, or freeze. Also, the spreads can be widely different around economic release time. Even in normal times there can be a pip difference between broker spreads. It may not sound much but if you save a pip on every trade and trade 5...
If you get an EA that works then awesome but if not then it could all go horrible long. If you buy an EA you are essentially handing your money over to an unknow system that you have not tested. Many EAs work great in trending markets but go horribly wrong in flat markets
I have traded different strategies on the same MT4 account and then make sure the strategies have a different magic number. I then use MyFXBook to analyse the results seperately.
I don't know about LMAX but for UK regulated brokers I like ETX ad IG Index. They have mixed reviews from some people but I have used them for years and have never had a problem