Spread/costs is what makes math negative expectancy in trading, just like zero in roulette.
example:
goal: 10 pips
risk: 10 pips
spread: 3
you need 13 pips move for your goal and only 7 to stop.
however it is true that position trading with large stops makes advantage of broker smaller but you will need good leverage and big account to survive.
Risk less than 0.5% if you want to be winner.
tihomir,
http://bgforex.org