I was at 1.50 with TOS for years. About a year ago (maybe a bit longer), suddenly TOS became open to lowering the rates. I managed to get down to 0.75, and I know many others who also managed the same. I also heard that some managed to get down to 0.60, but they were doing very large volume. I do not know if they are still quite as accommodating.
An added bonus for TOS, at least for me, is that customer support has been very good.
That said, if the smart routing at IB really is much better than TOS, that could make a big difference. Ergo, my original question.