I checked different broker price comparison at www.daytradingstocks.com I am now convinced that IB commission is friendly. Rate it A+++ If one trades cheaper stocks in larger volume, like WCOM or LU or NT, may be other discount broker like scottrade has better comparative advantage. But if one trade blue chips like MSFT or IBM in a lot of 1500 shares or less , Interactive broker is a better choice. Still it would be better for customers if IB sets upper limit on commission charge.
i can imagine that SSF's will help here in future day, maybe with increased contract sized (e.g. 1000 WCOM per contract) - if they are smart. unfortunately, IB's own costs for settling 1 WCOM are the same as for 1 MSFT -- except SEC fees, so i see no chance for a commission cap here, i do not even want one if it negatively affects IB's performance.