You keep saying that a benefit of IBKR Pro is "no PFOF". That's true --- IBKR Pro is I think the only online retail brokerage that doesn't do that.

To my understanding, the only meaningful benefit to "no PFOF" is potentially better price improvement. Which is to say, if you place orders with Ameritrade, which is doing PFOF, you're going to get price improvement over NBBO, but with IBKR Pro, which doesn't, you might get even better price improvement.

In the IBKR Pro case, that's true: according to their advertised price improvement stats, you will get 1/3c of improved price improvement per share as a consequence of trading through them compared to the industry average. Your call whether a third of a penny is meaningful to you.

But in the general case, it might not necessarily be true that "no PFOF" is a benefit; it's all a question of the fees you pay and the price improvement you get with a given brokerage's routing, right?

Am I off here? My sort of baseline belief is that firms like Citadel and Virtu are in fact very good at executing retail orders, and that it'd be weird to have a goal of making sure your dumb retail orders were routed around them.