I know a few guys that trade their own money at one of the well known "prop" firms. Their commissions seem to be in the .005/share area and they have the standard 4 to 1 margin. What are the advantages of this set up compared to trading with Iteractive Brokers (for example) as the costs seem to be in the same ball park? I can see if you had a mentor or a group of successful traders to be apart of and learn from but besides that????