Hi, I'm using Power E*Trade Pro (direct access platform) where I can choose four different ways to route my orders (AUTO, ARCA, NSDQ and NYSE). I'd like to know in which situation I would choose one routing option over another. I have been using the AUTO routing option. Is there any benefit of using the other routing options? I have recently switched from swing trading to mainly scalping the SPY with market orders, so I'm now more concerned than before about getting the best and fastest fill possible.