regarding SuperSOES.. i followed a link to IB (from another thread) and copied this paragraph:
"Please note that for Nasdaq stocks that are not National Market System securities (e.g., Nasdaq Small Cap stocks), NASDAQ's current SOES and Selectnet will remain in operation according to the same basic rules as in the past. IB customer orders in these securities that are routed to "SOES" will go to SOES, and orders routed to "Nasdaq" will be preferenced to a market maker or ECN via Selectnet"
so apparently when routing 'Nasdaq', if it happens to be a Nasd. small cap your order goes through Selectnet and could end up with a MM