The biggest drawback for retail traders is becoming familiar with a 3rd party platform and paying for it when others like TD and IB offer for free. Those platforms are awful, but we as an industry need to align ourselves with proper SPAN margin. Without doing this, TD and IB will always have an edge no matter how bad their platforms are. The margin for a simple call spread is exacerbated drastically. Imagine butterflies, I need my FCM to put clients at 10% margining and this should not be needed.