Quote from AAAintheBeltway:
I know this will be unpopular, and I admit I often try to get price inmprovement, but I've never considered it fair. If both sides are willing to deal at one price, why should the spec be able to favor one over the other just because he has a different agenda? I don't claim to understand all the wrinkles in it, but the Nasdaq/ecn model seems fairer to me.
When I trade listed stocks, I often put limit orders in and let them sit there for minutes or even hours. I never do that with four letter stocks. If my order is not executed within a few seconds, I usually cancel it.