From Investopedia
Cons: Market makers can present a clear conflict of interest in order execution, because they may trade against you.
They may display worse bid/ask prices than what you could get from another market maker or ECN.
It is possible for market makers to manipulate currency prices to run their customers' stops or not let customers' trades reach profit objectives. Market makers may also move their currency quotes 10 to 15 pips away from other market rates.
A huge amount of slippage can occur when news is released. Market makers' quote display and order placing systems may also "freeze" during times of high market volatility.
Many market makers frown on scalping practices and have a tendency to put scalpers on "manual execution," which means their orders may not get filled at the prices they want.
Cons: Market makers can present a clear conflict of interest in order execution, because they may trade against you.
They may display worse bid/ask prices than what you could get from another market maker or ECN.
It is possible for market makers to manipulate currency prices to run their customers' stops or not let customers' trades reach profit objectives. Market makers may also move their currency quotes 10 to 15 pips away from other market rates.
A huge amount of slippage can occur when news is released. Market makers' quote display and order placing systems may also "freeze" during times of high market volatility.
Many market makers frown on scalping practices and have a tendency to put scalpers on "manual execution," which means their orders may not get filled at the prices they want.