I have had only good experiences with TMBR so far, always instantaneous. HOWEVER, with supersoes a situation where my order seems to be "looked at" happens quite frequently. I realize I have said this before, and I realize there are people on this board who love to instruct me regarding SOES rules and regulations, therefore I will not say my orders are being looked at, only that they seem to be looked at, and I will just describe what I mean:
Sometimes IB is just a little slow (particularly at times of heavy volume). This situation can be recognized by the fact that my order for a nasdaq stock stays blue and on "BEST". Then, after a few seconds, I either get a fill or the order turns green and "ISLAND".
At other times, however, the order turns "SUPERSOES" immediately and after that it takes a few seconds before I get a fill or get rerouted to "ISLAND". I would think that the observed delay in these cases is not due to IB, and I also don't think a supersoes computer would take, like, 10 seconds to match the order and send confirmation. Of course I am aware of the fact (thanks to some very well informed people who keep reminding me of this beautiful truth) that supersoes is absolutely automatic (at least for the 100-share orders I am talking about), so there is absolutely no way a market maker can make money by offering or bidding on supersoes instead of, let's say, on the Island ECN. I guess it will just remain a mystery...
Seriously, I don't think MMs bend the rules, but I also don't think that supersoes (or soes) rules prevent your order from being "looked at" under all circumstances, even if its size is just the amount quoted at the time you transmit the order. In case you find that unlikely, just think about how many traders see a certain quote at a given second, how many of them try to take it at that very second, how long it takes the MM to change a quote, how long it takes for this change to reach each of those traders etc.
The bottom like is, a perfect broker would offer customizable sets of exchanges that can be configured to be considered for BEST execution. In other words, if I want to define "MYBEST1" as the best among {ISLD, ARCA, INSTINET}, then I should be able to do so and use "MYBEST1" for critical orders say in fast markets.
Of course, if you asked me if I would prefer IB's commissions and execution abilities to $.012 per share commissions and customizable sets of exchanges, I would not hesitate a second to choose IB as it is right now.