The kind of "Forex trading" you reference is pure Mook Skinning.
All serious Forex traders trade on ECNs...
Where the Order Book is comprised of all MM and Customer orders...
And the fees are $2.50 per $100,000 or less on volume...
(Googling "Forex ECN" can't be too hard...
Though a lot of Mook Skinners LIE and call themselves an ECN).
It's actually more complicated than that; even pure ECN brokers have an internal order-book which they match purely in-house as a market-maker. Of course they also have the ability to place your orders with a real liquidity provider, but whether they do that or not is a decision they take and not one you can control.
A good rule of thumb here is that any system for trading on a market which uses a read-only price-feed (as all forex brokers do AKAIK) is more akin to betting than trading, because you are playing against a closed system which cannot be altered by your own trades.
A real exchange is a totally different beast, you can affect the price and they don't care whether you win your trades or lose.
At the end of the day there are good forex brokers and bad ones, but the scope for them to be bad is very large due to the nature of brokers and the price feed.
My main business is trading stocks (about 500 trades/day)...
But I trade Forex every day on IB's IDEALPRO (maybe 10 trades/day)...
Which is what I call an ECN = "real exchange"...
My Limit Order has the same status as all other orders...
It becomes the bid/ask if its the best ...
And, of course, IB or anyone can fill it at my Limit...
Plus I probably get price improvement 20% of the time.
By contrast, Mook Skinners maintain a market with about a 2 pip spread...
So these unfortunate souls are paying $20.00 per $100,000...
Which is > 10 times what traders on ECNs pay...
A rate that dooms you to go broke eventually.