Anyone have any experience with getting limit orders filled at these brokers? Or other comments comparing them?
Why would a limit order get different fills at different brokers, unless the order is held in an option dark pool? If you don't get Direct Market Access, they send your order to the exchange that provides the best cost/revenue structure for them. The reality is that most executions that are not marketable at the time you enter it, get executed because the stock moved, and most limit orders will get filled around the same time.
Because there are like a zillion option exchanges and brokers are still selling their flow through the HFTs who have little incentive to place the order at an exchange which is best for the client.
I agree that option SMART routes are set up that way. An option MM gets first look and then settles on an exchange that works best for the route, as they have to cover any fees over PFOF. In general, the orders go to a small number of large MM firms, so many orders that are "SMART" are treat in a similar way. Not sure why the SEC thinks that 14 option exchanges, all owned by a few companies, is a good idea. I think it is terrible for the public.
The present market structure is imperfect, agreed, but think back to the treatment retail orders got before ~2001 when options were pit-traded... ouch...
Linkage of the exchanges "in theory" prevents trade throughs. So you should be no difference. Linkage would send out an error message if a trade though were to occur. So again under normal circumstances - no fast markets and no flickering quotes it shouldn't matter. Most of the Smart Routers will sendlimits to Maker/Taker variants of the exchange groups. One of the reasons why multiple exchanges have multiple models. Marketable orders o to payment exchanges. Limits go to maker/taker exchanges.
Whatever routing TD Ameritrade does with limit orders seems to be more effective than most. I am talking about getting a fill on the bid when very little trades on the bid. I have direct routed orders at the same level (different broker) remain unfilled, so I know it didn't trade through the bid.