I could be wrong about this, but switched from IB's SMART router which mainly routes to the NYSE to routing to ISLAND and ARCA on Genesis. At first I was so excited because I though of all the ECN rebates I would collect that basically my comissions would be free. If you are trading a NYSE stock and route to ARCA or ISLAND, the fact is you really just do not get hit unless the price trades through. I get filled much better when I'm routing to NYSE. I'm starting to think it's really not worth shooting for the ECNs on NYSE stocks... what do you guys think?